Paranoid about my partner and reluctant to talk

I have been with my boyfriend for 2 years. During the first stages of our relationship we were seeing each other long distance and he told me that we should both continue to see other people as the distance was hard. And we never really acknowledged our relationship as a proper relaitonship. When we finally did decide to make a commitment. I said to him that I would be faithful and I expected the same. This part was not an issue. When I moved (interstate) to be with him (now a 12hour drive away from my family) He started to get angry and frustrated because he had hang ups about all the guys that I had been with during the time we could see other people. He was really abusive and called me names and said that I should pay for what I have done. Anyway, he eventually got over it and we had had a happy and healthy relationship for a little bit. We discussed why he was so angry and why he felt like it was appropriate to call me the names he did etc. and he said it is because he is jeleous because I slept with more people than he did.
We then discussed the options of him being able to sleep with other girls (the concept of it does not upset me in anyway and I am no a jealous person)
We decided it would be healthy for the relationship so we made a rule of always ask the other person before doing anything. He went out one night and did not come home until the next day. I was so worried I called the cops. He then came home and proceeded to tell me he had been with another girl. I was angry and hurt as i had spent all night worrying about him. Now I am paranoid that he is doing things behind my back. I don't know if this is related to that night or if it is because of the things he said to me which caused a serious lack of self esteem. Anyway I know he didn't sneak around behind my back on purpose but now i can't shake the feeling that he is constantly doing it. Is there anything I can do (that is more productive than going through his phone) as i know he is not sneaking around and it is just me being paranoid?
I feel I cannot talk t him as he just asks me questions about why I am so paranoid and so upset and to be honest, I don't really know.