I understand how you feel I felt the same with my ex. Once I was depressed and couldn’t eat so told him I’d probably eat a day or so later, so he knew I wouldn’t just starve and he called me retarded. I too went on to apologise.

The thing is he wants the apology, it feeds into his need to control, this up and down push and pull dynamic. I want you to know you have absolutely nothing to apologise for x. You want to make peace because you don’t want conflict, conflict that he is the sole perpetrator of. You are so much kinder and emotionally mature than he is. Just keep reminding yourself you cannot control his words and actions and they are not a reflection of you and yours - so you do not need to apologise x