Have any of you had to deal with your surviving parent dating again? How do you cope with that emotionally?

There is a lot to unpack here. But let me say a few things first.
1.      Your mother – his wife – can’t be replaced.
2.      You have a right to your feelings – but so does he.
3.      Your wife is right.
So here is the thing. I feel like if you were a little kid, it might be different – your dad would need to focus on making sure that your needs are met and that you are taken care of first, and that he would need to be careful about who he introduced into your life.
But you aren’t a little kid.
That doesn’t make the change any easier for you.
BUT…
I think when you have someone who has fulfilled one side or the other of the very traditional role, they often seek out companionship – even quickly – because they need that other side filled. And they cannot fill it themselves. Even in your father’s case, when he has filled it when your mother was sick – it wasn’t a natural fit for him. My BFF’s mother actually shocked all of us by marrying rather quickly to someone who was well known to all of us for all of our lives and a recent widower. She had always been a very traditional homemaker. I’m not even sure he knew where the kitchen was. Their relationship started out as companionship and became love over time.
Conversely, my own mom – who was a fairly traditional SAHM when I was very young, but who became the EVERYTHING mom/wife after I started school, working, taking care of us,  taking care of the home, taking care of dad, etc – and then became Dad’s caregiver until he passed away – maintains that it is very unlikely she will EVER marry again – she is open to dating if the right man comes along, to go out and enjoy herself, but she never wants to be responsible for another person again.
Your feelings are valid, and you have a right to them. BUT…your dad is lonely. And not in a way that your or your siblings can fix. You stated that you and your siblings have your spouses for comfort. That is what is missing for your dad. And even if your dad is dating, his woman is not ever going to replace your mother. She is not ever going to replace his wife. EVEN IF he were to marry her – she STILL wouldn’t replace her. There is room in his heart.
When you and your siblings came along- his love for the first didn’t diminish or go away because a second came along.  And while I realize that a romantic love interest is different from a child – you have to realize that a couple of things are true. Your father is alive. He is only 72. Frankly, he could live another 20+ years (my grandmother is almost 100!). You mentioned that you thought he would move in with one of you and that would be the new family dynamic. While I know what you mean – I also don’t really think you meant you wanted him to be lonely for companionship outside of your family for the rest of his life. His life didn’t stop. He still has a lot of life to live. I have a co-worker that is almost 80. She doesn’t have to work. She could have retired a long time ago. She enjoys working.
So here is my advice. Have your feelings. But listen to your wife. Accept that your father wants to have a new relationship. Recognize that he has human needs for companionship (just like you do). Recognize that he is not trying to replace your mother, and is simply trying to live his life. Embrace the love that you all had/have for your mother. And LOVE on your dad.

My dad was true blue to my mom and she was to him. Mom outlived my father by many years and she was never interested in another man.

Now, my husband’s side of the family is a whole different story. My MIL was a remarkable woman who sadly died at age 68, with non Hodgkin’s lymphoma.

My FIL couldn’t emotionally handle his wife’s illness and sought out the comfort of another woman while his wife was battling cancer. The woman was an old flame from college who happened to be volunteering at the hospital where my MIL was.

He moved this woman that he was having an affair with into his house a couple of weeks after my MIL’s death.

She removed all of his family photos and replaced them with only her family. Yep! She even took down pictures of his grandchildren.

She bragged to us that it was so beautiful how he hugged her so tight in the hospital room when my MIL took her last breath!

Who tells a grieving family this? I will spare you the loads of stuff that our family went through.

So, be grateful that your dad was a good guy to your mom. He is entitled to be happy and find love again if he desires.

My FIL didn’t even wait until his wife died before he started seeing this woman. They could have kept their relationship discreet for a while but they chose not to.

Think if it was reversed and you're dad said you know what I don't like your partner you need to break up, I am assuming you would be horrified, you might even say well I am something years old and make my own choices. This is what would be said to you if you said this exact thing to your father, the thing is you could ask to meet his "friend" and get to know her a little it is scary, but you should realise that is just fear of the unknown, this "friend" isn't replacing you're mother no one can ever do that,from what I have read from you're question you're mother will always have a permanent place in you, you're father's and family's heart. Remind yourself your mother is irreplaceable.

Your Dad was good to your mom. And apparently had such a good marriage that he has decided he doesn't want to end his days alone.
Your Dad has a right to be happy. I think your Mom would want that. I hope he chose well. Please allow him happiness.

My dad remarried in his late 70’s. When he started dating, we told him his dates had to be older than his eldest child. No problem, he always dated women his age. He dated several women (starting a few years after mom died). We liked several of the women, a few of them, not so much. The one he did marry, we only saw her a couple of times even though they dated for several years before getting married. All I can say is, VET the woman if he decides to get married. We didn’t find out until years later what a grifter this woman is! So, if he gets serious about someone, have her checked out thoroughly as well as her family. We didn’t even think about the fact he could get involved with such an unscrupulous person; our family has zero divorces and zero drama. This woman brought all kinds of nastiness into our family.

Your Dad grieved you Mom long before she passed. She wasn't "there" for a long time. He took his marriage vows seriously. "Till death do us part" Your Dad is far from elderly. (I am 73) I remember reading once that a man in his 70s remarried soon after his wife's passing. When asked why he said "because you never know when u will die, and I want to enjoy my life till then.

Be happy for Dad. He loves your Mom no less. Let him enjoy the years that he has left. Men usually remarry or have companionship soon after a spouse passes. They can't be alone. Women, not so much.

I know what you mean. My dad developed a relationship with another woman after my mom passed. Shortly after, actually. I knew he needed someone, but it was hard seeing him with another woman.
When he, himself, became ill, his girlfriend helped take care of him, and I was grateful. But it was hard as hell hearing her tell me she loved him so much.
I know what you're going through. I guess they have a right to live their lives. We both know they loved our moms.

My dad remarried after my mom passed away. We all knew he would; he was lonely. We made one rule, all his dates had to be older than the eldest child !! He’s been married for over 10 years now and during this time, we found out what a horrible person she is. We had only met her a few times over the 3 years they dated before marrying and now we know why; she is a grifter with a past.

My advice would be, your dad needs someone so he’s not lonely. Someone to enjoy coffee with in the mornings, watch movies with in the evenings, have happy hour with in the evenings, etc. You (and your siblings?) have your own life and family and I would think you would feel guilty knowing dad was at home all alone every day. But REALLY check this person out and any person he dates before he gets too involved with her. Also, make sure his MPOA/POA has you/siblings listed and get and stay on all his accounts. It may be better for him not to get remarried and just live together. Although older people don’t like that living situation, it makes it a whole lot easier when they need family help later.

It just takes time for you to come around, but don't say anything negative to your dad. He deserves some brighter days in his life, out it doesn't mean he's forgotten your mom.

My grandfather remarried four years after my grandmother died and didn't even tell my mom or her sister until after it was a done deal. They didn't know he was dating, and he handled it all wrong. My mother always had a hard time with it, but my aunt was more pragmatic and welcomed his new wife warmly.

When my own mother developed dementia, she forgot my dad with a couple of months of his death and invented a new husband alrost immediately. That was absolutely heartbreaking for me and my brother, because she and Dad were married for 66 years and he was history within weeks.

Still, she was devoted to the new imaginary husband (a reimagination of her first high school boyfriend), and she was happy. In fact, after the year-long Covid lockdown in her memory care facility, the caregivers told me she weathered it better than most of the residents because "Dan" never left her. In the end, we'd grown so fond of this imaginary man that my brother wanted to mention him in his eulogy at her memorial service. (I vetoed that, since the details of dementia needed to stay private.)

Try to be open-minded about your dad's new social life. Be wary of any women who might be taking advantage of him, but otherwise give him the freedom to live again without having to worrying about how you'll react. He shouldn't waste away just because your mother did. He honored her to the end, and that's important, but now he needs to live.

I think your heart tells you he's disrespecting moms memory, but your brain is telling you "no he's not". It's ok to feel sad that dad's dating again bc it represents the end of an era and the end of your family unit as you've known it your whole life.

But remember that dad has had a very hard time helping mom through the end of her life which took a huge toll on him. At 72, he's still young enough to have fun and find love again. Definitely support him in this new phase of his life but don't view it as he's forgotten mom. He hasn't. Her memory with be with you all forever.

It’s a beautiful thing when a bereaved person finds someone to be with after losing a beloved spouse. Be happy for both of them.

Also be aware that this woman may enhance your family’s life. She may help your dad when he gets sick. She may be in need of a family to love.

If dad loves her, be grateful. He could be sitting around your house moaning and groaning and crying and getting sick. That would be ten times worse.

As a widow myself, I will say a few things that may help.

He's never going to forget her. It's been 24 years for me, and I still think about him every day.
He was with her until the very end, which is heartbreaking, trust me. It's brutal.
Marriage vows are "til death do you part." The vows were kept.
He will never find a replacement for his wife. Never. I've looked for 24 years, nobody can come close to the perfect man and relationship we had.
Think about loosing your own wife....the pain, sadness and loss. You still have her, sleeping next to you every night. He lost that gift of security.
He surely pretends to be happy, when he never will truly be happy again. He will put on a good act, like I do.
He is not disrespecting your Mother in any way. He did the right thing until she left this earth.
After his immense suffering, he deserves a tiny bit of happiness in some form. He lost half his life after loosing her.

Please be supportive to that bit of happiness he is trying to have with what time he has left. I'm sure your Mother would want that for him, and want you to feel the same. It's unconditional love.

Let it go. Give him the same respect he gave your Mother. He's a hero.

Hope this helps.