Let me share from my side... I think I'm terrible guy.
I have broke up with my ex... 20 years ago. And both of us having family and kids.
Sad thing is I never recover and I don't have any guts to meet her at all. And we never meet each other after that.

At the same time, I know every detail of her life and I just hide aside. Life still going on although emotional is suffering.
Rationally  I know this is not fair to my wife. Of course, I hide it very deeply and I know my wife can feel it and she dare not ask.