Husband gets off to his SA

Me and my husband have been going through a rough patch in our marriage. We are in marriage counseling and he sees an individual therapist for his anger issues. My husband sees a woman therapist and that made me uncomfortable. My boundaries were I prefer him with a male therapist but our marriage counselor basically said I was wrong. My husband had texted his therapist one day and I read those text messages yesterday. He said he wanted to meet with her more than once this week because he's been having a lot of dreams about when his dad used to sexually abuse him and he has been waking up hard or having wet dreams. Basically getting off to his own abuse. This upset me for multiple reasons. 1. He's talking to his therapist about sex. 2. WHY TF ARE YOU GETTING OFF TO MEMORIES OT YOUR DAD RAPING YOU?! I haven't spoken to him about it yet and I don't even know how to start that conversation.