I don't trust my boyfriend anymore, what should I do?

Hello everyone,

So I have been dating my boyfriend for 2 years now and we've been friends for 4 years. About a year into the relationship, I found out he was messaging girls on the website called InterPals. From what I read of the messages, he didn't seem to be flirting with them but he never told me about it and he hid it from me. I hated the fact that he went behind my back and felt the need to look for and message strange women. I broke up with him because I felt like my trust was betrayed. During this time, he was really sick and he said he needed someone to talk to without putting his problems on me so I forgave him and we got back together. I told him I wanted honesty in the relationship.

Although I have trust issues naturally and I am a very jealous person by nature, ever since I found out about him talking to those girls, I became more mistrustful of him. I would, in a state of paranoia, constantly check his phone, go through his history, check his Facebook and confront him about it. Granted, I had his Facebook password and the password to his emails. If I found out that he was talking to other girls I would freak out on him. I would confront him asking him who they were and I admit I tended to overreact. I overreacted too when he would talk to one of his friends that has been there since the beginning of our relationship. But he didn't want me looking at his phone or checking his stuff. He didn't like that I was infringing on his privacy and I agreed that it wasn't healthy. I requested that he tell me everyone he talks to (well girls that he talks to) and show them to me to make me feel at ease, and if I ask to show me his phone and the messages. But we had constant fights about it and he said he had no reason to restrict his life for me, he could talk to whoever he wanted to because they are just friends, and that he will not tell me who he talks to because he has no reason to do so and it's unhealthy.

I had become better and less paranoid. I began to trust him not to talk to anyone, but I would still ask him who he talked to, and he would either say "I'm not telling you" or "No one."

A couple of days ago, he told me he has a friend he met on the InterPal website when we broke up. He kept talking to her throughout our second go at the relationship. He never told me about her. He used the app Kik to talk to her, but when I asked him about it he said he used it to talk to his other friend who I know. That, however, was a lie because he was talking to this girl the whole time. Even when I asked him who he talked to he said no one. And when I would confront him he would say he wasn't going to tell me who he talked to. According to him, this girl is a lesbian and she is just a friend. He said he hid their friendship from me because he knew I would overreact and freak out and he didn't want me to break up with him. He admitted to purposely deleting the conversations so I wouldn't see them. My question is, is this right? I broke up with him over it. I mean come on, 6 months of a friendship with someone and he didn't think of telling his girlfriend. ESPECIALLY a girl he met on the website that broke us up. According to him, it is because I am too jealous and cannot handle it when he talks to another girl.

My problem is not that he has friends that are girls. Yes, I do get jealous when he talks to other girls (even if they are just friends) and I know my jealousy can be irrational but eventually my jealousy goes away, but it makes it especially worse when I'm being lied to. I've been working on my jealousy problem. He said that it's because I had gotten better that he told me about his friend. But I still feel betrayed, I mean it was a 6 month lie.
He is now telling me that he will tell me everyone he talks to and not lie to me, but since it's the second time happening I am very wary. I don't know if I am overreacting or if he is just lying to me. My biggest fear is that if he lies about insignificant things like this, he won't have a problem lying about bigger things. I just want to know if I should move on or try and work it out with him.

Thank you!!