Feeling stuck and sad about the past

[StretchVelvet]

NC because I suspect I sound pathetic .

I recently found the Facebook page of an exBF that I have never really got over. It's been many years since we were together (decades) and during that time he was often in my thoughts but I just accepted that I was never going to completely forget about him, and that he'd always have a little piece of my heart. Ours had been a very intense relationship and at the time I was too immature to sustain it.

I got divorced several years ago, and looked for him online then, but didn't find anything. Unfortunately he's got a very common name which made it very difficult. We grew up in the same area but I had no idea where he's living now. Anyway, I recently found him on FB, completely by accident, looking at some pics of one of my old friends from school. He doesn't have much info visible on the public setting but he has posted two pictures of himself and even though he's now in his early 50's, he's very attractive and I got butterflies when I saw him.

Sorry this got so long, I'm not even sure what I'm needing here. I always felt like he was the one that got away, I never forgot him, I felt bad about how I'd behaved during our relationship. I suppose I'm hoping someone can help me to just put these feelings away, and not feel sad about this any longer. I just don't understand why I can't leave the past where it belongs.
I've had plenty of other relationships before and after this one, but why has this one haunted me for so many years after it ended.

I should add that I've got no intention of contacting him as he's in a relationship.

Thanks for the support Potion.

I've been thinking it over this morning and I'm concerned that I'd be on shaky ground if I contacted him while he's in a relationship. Although I agree with hippo that people don't always update their status.
Let's say he suggested meeting for a coffee for a purely platonic catch up. I've still got feelings for him, what if meeting him makes them stronger ? He's with someone else, I can't have any expectations. I know that meeting him may be the opposite and I may think 'yuck' (so may he!). But I feel a bit too vulnerable at the moment. Maybe when I've spent a bit more time getting myself 'sorted' I'll feel stronger.
Anyway, no firm decision either way, just overthinking (as usual!).

How old are you stretch?

nospace let's just say I'm middle aged, the wrong side of 40. Going through lots of life (and body) changes and my self esteem is on the floor at the moment.