Bf problems

So, not long after I had our son I found out that my bf was liking and saving pictures and videos of other girls on TikTok and instagram. And I know for some people it’s easy to move past that but for me it hasn’t been. I don’t trust him anymore. Because not only was he doing it while I was pregnant and after I had him. He lied to me. I expressed how I was insecure about him cheating and things exactly like that during my pregnancy because you hear about that thing all the time. And he would say “oh no babe. Idk how guys do that to their girl. I would never do that to you you’re the only one I look at/want” but it was all bullshit! and I feel like I’m going insane you guys. Like I don’t know what to do. I don’t trust him anymore because now that I’ve outed him he knows exactly what to hide. And it tweaks me out because I felt so secure in our relationship. And now I don’t. Idk. Maybe I’m overreacting maybe I’m not. But I hate that this how my brain is.