Needing advice

My male partner and I have been together for 9 years. I am female and 10 years younger than him. Early on in the relationship I began to suspect he was bi as i am it disnt appear to be a big issue. The only problem now is I believe he is gay not bi. Our sex life is sporadic at best. When he is drunk and we are having sex he talks about being with a man. He says really graphic things. We went away on holidays to the beach which I love. He found out there is a nudist beach and became extremely excited and asked if i wanted to go check out some cock. When I ask him straight out if he is gay he avoids me and becomes angry. I just about have to beg to get sex. As soon as we have a conversation about being gay all of a sudden he wants sex. He is terrified at the thought of anyone finding out he has had sex with men. Any advice please