What do I do???

I’ve never written or posted on this before but I’m really struggling and really stuck. My boyfriend and I had been dating for about 9 months. He has always been really really sweet to me. Long story short was overall a good boyfriend. Aside from that he has put me through some shit and messed up but we all do. And everything he has messed up he would fix it and fight extremely hard to make sure he had me back and I felt safe. He never cheated on me or anything but he’s messed up(I won’t get into how) back in March we kind of got into an argument about checking other woman out. Idk about anyone else but I feel if you’re in a relationship you shouldn’t want to check anyone out. Yes you can acknowledge beauty but I think there’s a difference between that and really checking a girl out. I would always asked him after the fight if he did and he swore on everything he didn’t. And would always make me know that I was the only person he ever wanted to look at. Two days ago I found videos and pictures of girls w big asses and shit in his history and on his phone. Like it was even porn it was literally just hot girl bodies. It really hurt me. Because not only was he completely analyzing other woman but he lied straight to my face about it the past 5 months and told me he was fighting for me after all the other shit he’s done but yet he was watching videos!! I broke up with him and he’s begging for me back but I just don’t know what to do. If anyone have any advice id really appreciate it