I wouldn't say forget the past entirely. Sometimes reconnecting can be a good thing. There's someone who I reconnected with after my divorce, unlike your situation we split many years ago because she had a golden opportunity to better herself which involved her moving 1500 miles away. I didn't stand in her way; if I had, at some point she probably would have hit me over the head and said 'you SOB I could have been something'. I have never forgotten her and unless galloping senility sets in I won't. But while I was married I made no attempts to contact this girl. It was pretty obvious even to somone as dense as me that to do so would have probably destroyed my marriage and I wasn't going to take that chance. (As it turned out, that wasn't needed to wreck my marriage.
But that's another story.)
Back to ths girl: we have both moved on with our lives, she's done very well for herself and I'm proud of her. We stay in email contact, just keeping up. I don't see anything happening other than friendship, but that's not the point, ya know?
Along the way I also caught up with her mom and sister, who I always got along with very well. It's been nice.
But there's a couple of girls out there where the breakup was, to say the least, stormy and if one of them were to pop up on my (admittedly not very often visited) FB page I'd just have to block them or ?? From your description, this sounds like that type.