How do I overcome the insane amount of grief and resentment after I had to end a relationship with a mother enmeshed partner

So I (30F) have broken up with my now ex bf (29M) three months ago because I couldn’t handle the enmeshment of him with his parents, especially his mother who had great potential to become a justnomil, anymore.

To keep the backstory short: throughout our relationship of 5 years (living together 3 years) I discovered that he lacked basic adulting skills at and around home, I figured out that his mum did everything for him up until we moved in together, his parents both guilt tripped us (but especially his mum bc his father seemed like the enabler pleasing the mum) to come visit them every weekend, His mum demanded every Christmas needs to be spent at theirs and threw a fit when we wanted to plan differently, she cried when he moved out, when we stayed over weekends she cried because we would go back home and she told us some sob stories how her extended family is not close anymore, after my bf and I moved together I noticed it got worse and his mum made petty comments towards me and asking why I get this and that from my bf and she did not. She guilt tripped my bf to visit her although she was sick in mothers day with covid risking to make him sick as well, she literally told him she was scared he would move out one day (like … Is he supposed to live with her forever?) and I think the moment I really didn’t see any chance anymore was when despite all the problems we already had, my bf proposed that we would move in with his parents in a couple of years and live with them, because that’s what they wanted. Hell no.

I tried so many times talking to him, establishing boundaries, trying to make sense for him that it is normal to move out one day and live your life and still visit your parents but without the fear and obligation. I tried to get him to understand, that his parents also had the opportunity to live their lives and build a family and I asked him: did your mum have to spent every weekend and Christmas with her in-laws? Well No she did not.

I tried therapy with him but he has this thing where he has a complete shut down, where he legit doesnt talk or he would just stare back at you or need like 15 min to form two sentences when it comes to the topic of his parents or resolving conflicts. He can’t really articulate himself and legit slurs his words so you can barely understand him. Our therapist suggested to continue with him alone and after a couple of session he backed out.

I reached my absolute limit. And I had to break free from this and live my life and protect my health, so I broke up. I still feel a tremendous amount of grief and resentment because I was deprioritised and invalidated emotionally for such a long time. I felt like a literal side peace bc my ex always made sure he made his parents happy. It was almost as if he was an addict and would relapse and couldn’t think for himself. My heart just hurts and while I know this would be best for me, I also feel guilty bc now he is back with his parents and I don’t think that is good for him.

But for now, I just want to get better. How does someone cope with the rollercoaster of emotions and the trauma of being a partner of someone enmeshed? Any advice or resources would be appreciated bc I am losing sleep over this like insane.

I already signed up for a talking therapy kind of thing that is easily accessible and covered by my employer where I live. But that is limited and actual therapy has a crazy long waiting list in my country. I just want to get better and have ways to cope and not think everyday about the grief, resentment and lost hope that we could have just had a normal relationship if his parents would have just left us some room to breathe.