How are you straight if you only have sex with other men?
What the fucking fuck?
One's sexual behavior does not have to correlate with their sexual orientation.
People have sex for many reasons. For example, a masochist might enjoy receptive anal sex without being sexually attracted to whoever is penetrating them. They get off sexually to experiencing pain. A masochist might enjoy penetrating someone via anal intercourse without being sexually attracted to whoever they are penetrating, but inflicting pain gives him/ her sexual pleasure.