Has anyone else experienced this?

Im a 20 year old guy going through college. I have known I've been sexually attracted to men since I was about a freshman in high school. I dont deny im attracted to men. I have had my share of sexual in counters with other men. However, my question is I cannot see myself having a long term relationship with another man. Like when I in vision my future I see myself with a beautiful girlfriend who I can travel the world with. I don't seek any relationship s with men other than a hookup. The thing is the first time I got in bed with another girl in high school, I couldn't get an erection. Ever since then ive been terrifier to embarrass myself like that again. This makes me question if I am truly only attracted to men or do I suffer from ED. Yet when im with a male I dont have a problem getting it up. Did other bisexuals go through this? Or is my mind still in denial that Im full out gay and won't picture myself with a man for the rest of my life?