How to fix resentment in marriage?

My husband resents me for an abortion in 2010. We were dating a year and we were to young and weren’t ready. He wasn’t completely for It but supported and went with. 6 years later (not married) we broke up for the resentment. Two months later he reached back out, we talked and decided the past is the past and moved forward. We got married in 2017 and discussed moving past the issues again to be sure he was certain. We have been dealing with unexplained infertility issues and don’t have kids yet. Miscarriages and failed

IVF

transfer. Well this past week he found out his cousin was pregnant and It seemed like It triggered him. Now he’s shutting me out, talks about divorce. I know he needs to work on these issues within himself. I’m just looking for some advice. Thank you. I should also add that he is not fond of marriage counseling