I can't say I would change anything, as that might have changed my entire future afterward, and the thought of not having my kids around...the same kids, not different ones....man, that would kill me, I just can't see myself not having them around. Shit, my son is my little mini-me.
That said, there are a few ex's I'd have cut out of my life if it meant I still got my kids years later.
I guess another thing would be not travelling as much these later years like I did when I was younger.