How to move on

So when my boyfriend and I had been together for just about 6? Months I found out he was asking girls for photos..... we talked about it and of course he said he wouldn’t do it again but just before we hit a year I found out he had never stopped. Now we’re at a year and I found out that the day I found out he was still asking for photos, he had asked a girl for some. I’ve never had trust issues before but now I find myself constantly going through his phone. I can’t trust him and I don’t know what to do, breaking up seems like the easiest option but I can’t bring myself to do it. I don’t know how to stop being so paranoid