Caught my boyfriend texting his ex behind my back?

[immenseMercenary950]

My boyfriend and I have been going out for over a year and a half. In last November was when I got the biggest wake up call of my life. Him and his best friend had a fall out, so his now ex friend texts me saying that "your boyfriend has been playing with u" and named each girl he kissed or did other things with. Well i facebook messaged each girl and heard back from 2 (there were 3) one told me she kissed him and she had no clue he had a girlfriend. And the other told me she knows him through her bf and never did anything with him besides sometimes her and her bf meet him at a bar. (Which i also didnt know about) anyways i confront my boyfriend and he tells me he was wrong for not telling me but we had been broken up for a day and i have done the same thing before (but we were broken up and i told him about it right away). So just yesterday after having more trust issues i finally had the guts to go through his phone.. I learned he was texting many girls.. Not sexually but randomly just trying to start convos.. And i went through his fb messages.. And he was messaging his ex.. And even said "i love you too when she told him she loves him" i was so hurt and yelled at him. I don't regret going through his phone because i never did before and i knew in my head he was being fishy. I'm so upset and he's been trying to apologize saying he deleted them all and he was wrong and that he truly loves me. What should i do since he keeps trying to prove himself to me??