Why is this guy trying to come back now?

okay so a few years ago 2-3, i was seeing this guy i had known for years. i went out to visit him where he was working at the time. i also had a girlfriend there so i metup with her as well. and somehow they got introduced to eachother. they ended up hooking up in front of me and dating for like a year and a half . i was sooo mad and so hurt , i never spoke to her again, and just recently carlos has been trying to talk to me(the guy). my girlfriend* ex friend* has a baby now with a nother guy and about to be married, and this guy has a girlfriend as well. hes been emailng me a lot lately. seeing how im ';doing'; trying to be friendly, saying he wants to move back here at some point. yet he has pictures of him and his gf kissing on facebook. i think hes regretting what he did to me i told him id never forgive him. do u think he just wants to be clean of what he did, or do u think that hes getting bored of his new girlfriend?Why is this guy trying to come back now?
well most likely he just feels bad for what he did. but who knows.. he could possibly be getting bored of his new girlfriend but if he's got pics on his facebook i doubt it.