Am I over reacting ?

So I got on my so's Facebook , I had never done it and I've always had the password but in Saturday a "friend" persuaded me into doing it and I went ahead and got on it and went to his messages . I saw that we would try to a lot of girls and it broke my heart ! All he would tell them was "hey I would like to get to know you" "hey can we talk if you would like to" nothing bad but I just got so hurt from it . Then I told him that night and I said I was done cause it's like he cheated and he cries so much telling me that I was the one he wanted to marry and that he'll delete his Facebook and won't talk to any of them ... I fell for it and forgave him .. Then last night I picked one more time and saw that he tried talking to two girl , and I just sent him a message saying that he was never gonna change .. But he was already asleep so hasn't seen it .. Am I over reacting ? We've been together for almost 3 years and is the sweetest guy , and I could have sworn he loved me and was serious about everything .. Idk what to do ,