Been there, still am myself to some extent. Sorry. No words of wisdom here, many more have provided those below. This is the song that the former, thought-it-was-for-life relationship haunts. Lyric video, just close your eyes and let it flow.

Some very good comments here, I concur with what many are saying. I wanted to add some things... I know, for me, living in regret is very painful. We all wonder about "what might have been." But maybe you did at the time what you felt you needed to do, maybe you weren't ready, maybe the timing was off, maybe it was so many things... All you can do is find strength and understanding from the decisions you've made and use that to help you move forward. Maybe you need to resolve what happened with him, maybe you don't, but right now looking backward and lamenting is keeping you from moving forward. You've put this experience in a bubble that nothing can compete with. But you were also a different person then, and who knows what will happen in the future.

I think the first love often is the one that leaves the deepest emotional scars. Once you are scarred once, the rest seldom cut so deep.

Timing and place do not always line up and distance makes things worse. I am sorry to hear your feelings but I think the comments below are spot on talk to someone. I am fairly new to the site but one of the most refreshing things was that nobody is going to not do anything aka. "Thoughts and Prayers".
Controlling the mind and heart are never easy things to do, not because you are weak but because you are human. You have thoughts, you have emotions and it is ok to express them in a safe environment. I feel the most sorry for the other woman. Being married to a man who loves someone else more than she must not be easy especially because my guess is she has no clue. Moving on is never easy.
Finding new people to interact with, not just virtually, even if not emotionally will help you take your mind off him and you will see little by little it will go away. But here is the catch. Cut all communications. It is easy for him, he is married and "pseudo happy" but you, you are left waiting. Cut all ties, it is safer for you and when you do meet someone, it will be more fair for them. He will always be in your heart until the day you die, but someone else one day will have a special place in that heart too.

Based on the comments, you're doing the right thing working on it. Anything that you can do to get over it will make it easier. It always takes time to get over loss, and we all work at our own pace.

First don't be so hard on yourself. You can forgive yourself and you may have done the right thing, but you'll never know. Maybe something tipped you off that you didn't consciously perceive or it just wasn't right.

It's too easy to second guess after the fact. Give yourself the benefit of the doubt because sometimes being lonely gives one a slightly skewed perspective on past relationships.

Finally, you did the best you could at the time and made the decision based on what you knew then. You shouldn't blame yourself for not having the same understanding that you do now. Just be forgiving with yourself.

Yeet

I'm in agreement with the answers provided by everyone on this thread. I'm just going to add my support and say I understand and feel your pain. I'm not sure which is more brutal - love environment or the workplace.

There is an old saying, " We can't choose who we love." I couldn't agree more. Our minds know it's a train wreck, and yet here we are.

Talk to a therapist.
You've got to find a way to let this go and move on.
You aren't doing yourself any favors hanging onto this.
Lamenting lost love is a complete waste of your time.
Figure out what you were supposed to learn from this, take it,
and apply it to your future.
Anything else is detrimental.
Talk to a therapist.

I have feeling like that about a previous love. In my case, she has broken off with me, and I can’t just call and she’ll be back. That makes it worse in some ways. I feel rejected.

I feel you.

It's not healthy for you to ruminate on this, do as the girl from Frozen says and use this song as your new motivator "Let it go"

When you look back, take off the rose coloured glasses.

When I split with my wife there was always a guilt there, and this made me think of her so fondly. Years passed, and every two three years we’d bump into each other .. and that bitch would savage me. Last time was a year ago, we split 20 years ago.

This time, and for all time I’m remembering why I left.

You too had a reason to leave, give it time to mature.

PS: Don’t play the song. We all have a B17. You’ll know when you can play it again.
Best.

I’m sorry for your pain and regret. I can also share, having been in your position, that kicking yourself over what might have been doesn’t help.
It wasn’t the distance; if that was the only reason, either you or he would have moved closer. There was a reason you didn’t marry him, and that hasn’t changed. If he were single now, you'd enjoy a reunion and then whatever wasn’t right the first time would show up again.
You can find love and chemistry again, but you have to see that first love as just that: the first relationship upon which you have grown into the next.

Break ups suck but the alternative is much worse. Your single embrace it. There are tons of fascinating people in the world. Around 8 billion actually. Lets say 4 billion for the gender you want another 2 billion set aside for age discrepancy. That still leaves with you with 2 billion people you can mingle and have fun with. Enjoy it ?

It is harder to face things when you feel that you are the one to blame, but you have to accept the truth is that we all make mistakes and that forgiving ourselves is the most important form of moving on there is. There is no act of forgiveness more important than forgiving ourselves. You have to teach yourself that your loss and the reason for it, are two different things which you have to deal with differently, otherwise they will keep on feeding each other in an endless loop. Moving on means accepting that these things are now a part of you and your history, and that you have learned and can grow to be better and stronger now you have more experience. Saying to yourself that; now thanks to my greater knowledge I am a far better more able person who can make a better job of future relationships and give a lot more to them, and therefore I can aim higher. Good luck with your search.

Maybe you haven't found your true love. That love the will eclipse all other loves

I have faith that you will.

Hugs be kind to yourself xx