Can you gain trust back?

I have a boyfriend who was caught talking to other girls. He lied a lot to me about it until the truth finally came out. Most people can’t forgive like I can but I am a very understanding person and there’s a lot to it. I’m making this post because I want to know people’s thoughts on gaining trust back? I seem to still be driving myself crazy every time he is on his phone. He does let me look through it when I ask (which I’ve only done once so far as this happened like 2 weeks ago) but I also know it’s pretty fucking easy to hide shit. I’m taking a huge fucking risk staying with him but I do understand the risk. If something happens again, it’s on me. I’ve definitely allowed myself to be in this position. I just don’t know if I can ever fully trust him and that’s not a healthy relationship at all. I’m obviously trying but idk if it’s always going to be in the back of my mind. Anyone else take a SO back after cheating (emotional or physical) ??