Hmm... Well I had similiar situations growing up though not with a cousin. I always wanted to "play" with my male friends and then in junior high and high school had girlfriends that I would never touch. If you are attracted to the girlfriend and love her, than I would say that it is a problem you need to address. Like alcohol, sex can be a drug and since you are young you probably have a lot of hormonal issues. Either persue the gay life with men or give it all up and be devoted to the girl. There are many men that fight their same sex attraction despite being married and go through a lot of counseling. I have met them, and in the end that is not for me and I woulkd like to just be gay, with or without sex involved. It is who I have always been and I struggle with it like many others.