Seeing the people you've had sex with before?

I'm almost 24, I've been with 7 guys. When I see someone I've been with I try my best to ignore them like idk who they are. Idk why, but I just do. Most of them where the type who just tries to fill your head up to get what they want. It's just awkward to me, and especially my last. I was with him for 3 years and it ended bad, long story short his best friend ended up telling me all the shit he was talking about me and it ended bad for the better... Now I am with the same guy for going on 2 years an we have the best relationship.