How do i stop being codependent?

I'm newly joined in this community and I'm looking for some advice. My 72 year old husband and I have been married 40+ years and it's been really rocky. He has not been diagnosed as being autistic, but he does check so many of the boxes. He has always refused to entertain the idea of any therapy because "there is nothing wrong with me" and because of course I am the cause of all our problems. In his eyes anyway.
Whenever we have a blowup I always end of apologizing for any little part I may have had--even if it's to take responsibility for not fixing the results of his hurtful behavior. Yeah, not very healthy on my end. Sorry if this isn't the community for this, I'm just really hoping to hear from others who have navigated this and came out ok.