What do I do?

About a month ago, I found tons of saved videos of naked girls on my boyfriend’s phone. I confronted him about it and he seemed to genuinely feel bad. I don’t know how to trust him again afterwards though. I’m scared he’ll do it again, and furious because we’ve been together for two years now. He told me it was a bad habit and he didn’t pay attention to what it was, he just automatically saved it because that’s what he used to do before we were together. We were long distance for the first year, then together the 2nd. And that whole year we’ve had fights about it because we’d watch videos together and those would come up and I know how the algorithm works. I’m mostly frustrated that all those times because I trusted him, he made me believe that it wasn’t his fault, and those just popped up and he didn’t know why. And I apologized for yelling at him every time. For a year? And it never occurred to him to stop this so-called “habit”?? The 2 years we’ve been together?

I’m scared to be manipulated again. Because it happened so easily before. I want to believe he’s genuine, but I don’t know how to start trusting him again without constantly suspecting him.