I (33F) don't like that my bf (38M) never apologizes anymore

My boyfriend and I have been together for 1.5 years.

When we get into fights, I quickly get fed up and overwhelmed, and storm away because I have nothing to talk about. I shut down, and don't want to say anything because he disqualifies everything and redirects the blame on me. When I try to talk things out, he never apologizes for anything anymore. He has been in an abusive relationship in the past. Is this a defense mechanism/a control thing?

tl;dr: My bf never apologizes anymore. He has been in an abusive relationship in the past. Is this a defense mechanism/control thing?