Someone please help me!

I’ve been dating this guy now for about 4 months. He makes me extremely happy all the time & does his best to keep it that way. He left his girlfriend of less than a month for me, & gave me his virginity. But the thing is, I am probably the most jealous girlfriend he has ever had because of a relationship I was in for 2 years. I hate it when he just talks to girls! But the other thing is, he has cheated on me twice. About 2 months into our relationship. Swore up & down he would never do it again, he hasn’t as far as I know. I also found emails from a dating website in his email.. Which doesn’t help at all. I feel as if sometimes he doesn’t really love me, want to be with me nor be around me. He claims he does though. I can’t stand to see his ex girlfriends, & I can’t stand knowing that he probably has said the things he says to me, to them.. I saw pictures the other day of the girl & him he was dating before me & it really upset me. Because of my jealousy issues, I have never been so confused in my life. Whether or not to just let him go for the better part, or try to continue to make him happy & feel loved.. I’m so sick of these mixed feelings of not knowing what to do. I need advice, someone please help.