Relationship advice please

So I’ll start off that I’m not the best at explaining things but please stay with me lol

So I am a 25 year old female and my partner is a 26 year old male. We have 3 babies and have been together for 8 years. Throughout our whole relationship he has dealt with “commitment issues” weather that be anytime we get into an argument he asks “well what should we do, what do you want to do” implying that we should break up. And the other commitment issues is him “emotionally cheating” he has messaged other women online multiple times and has even receive and sent nudes. ANDDD the times that I caught him was either while I was pregnant or postpartum or both😅. So here recently (like 10 months ago) I caught him again, this time he was on some website making plans to meet up with a couple😅. Anyways after I happened to catch him, he said it’s just something men/him struggle with and that he knows it’s wrong and it’s something he will change and stop. So fast forward to today, i woke up and he wasn’t there, he was in the bathroom which isn’t unusual for him to do but i got a gut senses that something was up and so i went to go peak on him. The bathroom door has one of those old key hole door knobs and i thought id just take a peak to see what was up. As im there loooking through the peephole I see him scrolling on some dating app or dating website idk and clicking on multiple different women’s pages and going through their story’s and picture, then he’d find one he liked and follow them or something and then send them a message. I already knew I was gonna confront him about it and decided to get my phone out and record what he was doing on his phone for “evidence” bc he loves to gaslight the fuck outta me when he is caught. Anyways, he comes down and notices I’m off and i ask him to step outside. I confront him and right away he is denying. Then he goes off on a rant of men just like to look and that’s all he was doing and that I’ll never find a man who doesn’t look and if I happen to find someone who doesn’t that he probably is but behind my back. Just being a complete dick about it. And now I’m really stuck with knowing I need to leave because he will never change and if he wanted to he would have a long time ago. The problem is we have our 3 babies and I don’t want to put them through having their parents apart but i also don’t want them to see our relationship and think it’s normal. My question to you all tho, is this a normal thing that most men go through and deal with. Or is it just men who haven’t matured enough to see that just because “everyone else” does it doesn’t mean it’s okay for them to do it. Idk guys give me your opinion 😂😅 also sorry if I didn’t make much sense