AIO refusing to get back together with ex after what I thought was cheating?

I think i just need some clarity before I make a mistake.

My ex and i were together 3.5 years, living together, had kids together (eldest is mine but his step child, youngest is his)

He was a good friend and a fun dad, but he also wasn't a partner. Despite him working, at home he became lazy, drank beer, smoked weed. Note: I am not against this form of relaxation, but i am against it when it makes you unmotivated to do anything else and frustrate easily, which it did on him.

We broke up 3 other times before this final breakup because it was my 'self defence' - I was also not the best partner

We initially broke up because he made porn "personal" which means im fine with porn so long as you dont over use it to the point it affects everyday life, do not comment on posts/videos, do not message anyone / flirt behind my back and do NOT buy content. Which he done all of this.

He wasn't paying any bills because I hated how stressed he got when bill money left his account. So he wasn't paying for anything other than a bit of food.

After this break up, he now no longer can stand the smell or sight of weed, he hasn't drank, he goes to the gym, he actually makes eye contact when I talk, he rarely doom scrolls, hes more patient with the kids, hes more active with the kids, hes paying a couple debts that we caused together and refusing any help on my part because "ive paid enough " he tells me that despite us being broken up, he wont ever move on and if he does it wont be as genuine and he will "wait for me" even though im in a situationship after 2 months of being broken up (just for my physical needs)

Like I say, I got toxic as well, after I found the payments and the many messages, I would check his phone whenever i could, I hated it when he went out and would say its fine but then give the silent treatment when he got back because it was late, I stopped enjoying time with him because I couldnt look him in the eye and I genuinely thought every nice thing he done for me, was "paying back" for disrespecting me and breaking my boundaries. I was also 9 weeks pregnant with our youngest when I did find all this out, so hormones took a major place in it all as well as post partum.

I am actually doing much better mentally, I have no commitments other than work and my children, but the way my ex is acting is making me think im overreacting about if it really was that serious, and seeing how much hes changed, and how genuine he seems, i kind of wanna give it a shot again?

But then like I say, im in a better place myself.

So AIO about the situation, or should i remain single?