BF is secretly watching transexual porn

Hey
My bf of almost 8 yrs has recently been secretly masturbating to transexual porn. I found the websitez he visited umder his google web activity. I have had a problem with substance abuse and recently using again. He has given me momey to get it mord willingly than ever and it takes me about an hour to get it and come back. I noticed he watched them while i was gone so now i know why he gave me the money without fighting...he obviously masturbated while i was gone. Watching porn isnt the issue, its the girls with dicks that bothers me. He is always acting grossed out by gay guys yet he is into trannys! My question is should i say something or act like i dont know? I cannot fulfill that fantasy for him bc i do not have a cock! I caught him looking jp tranny prostitutes on backpage a few yrs ago but he said someone else used his phone. Now i know that was bullshit. Please tell me how to approach this.