I let him back in and now I am kicking myself

We had separated for 6 months and he moved out in November of 2020. There was an infidelity on top of abuse, so I kicked him out. He promised he would go to therapy with me and individual therapy for himself to make things right and to work on himself. He had owned up to the abusive behaviors, so I thought there may be a chance.

We got back together in June 2021, and he moved back in in March/April 2022.

There was a big fight in April that he started, which planted yet another seed of doubt. But we got past it and it was smooth sailing from May-August. Then in late Aug/Sept he started initiating fights with me - many fights, at lease once per week. He got nasty in these fights, called me names, insulted me, demeaned me, used gaslighting, projections, blame and accusations.

After the 5th or so fight, I decided I could not trust him to not be abusive. Therapy was a total waste, and he wasn't putting in true effort - he was only trying to appease me, I realized much later. He hadn't changed - not much and not enough. More broken promises, and I had had enough.

So, I've called it quits again and we are officially separated in the home. We are stuck together until one of us is able to move out, and our lease doesn't end until June. One of us being able to move out is complicated.

I am kicking myself for letting him move back in, and for letting this a-hole back into my life for a second time. I am very frustrated and am angry at myself for wanting to believe in him again, especially when his words are just that - only words and empty promises.

How do I forgive myself for doing this yet again? Now we have to go through the separation and moving process a second time. I cannot seem to forgive myself and I think mostly that I was being seriously stupid, acting on emotion vs logic.

How do I get past this self blame and guilt?