Can my husband accuse me of adultery, or can he try to get alimony after four years of separation?

My husband and I were divorced in 2016. Basically, I left him for another guy, but there are rumors that I was cheating on before we split. I dated the other man and became pregnant 4 months after I left my husband. I’ve been separated for four years now, and my husband even told me that he blamed himself for the reason I left him. My husband and I have never filed a divorce on financial grounds. If he decides to file for a divorce, can he still accuse me of adultery or ask me for a pension? I’m pretty sure he can’t do that because it’s been so long. He told me he was going to get back together.