Still think about my ex??

I've been with my boyfriend for a year now, and he's such a gentle man. He's an example of the perfect guy. He loves me so much. But sometimes I find myself sorta thinking about the guy I was previously with. I left him but he has a girl friend now. He was a player and constantly lied to me and hurt me, and I always felt I wasn't good enough. But when he tried he was charming and sweet and it pulled me in closer. I don't understand why I still think about him. I gave him up to be with my current boyfriend because I thought I deserved better. I just never wanted it to come to that. What should this tell me?