I want to have with my gay mate?

So me and one of my best mates goes way back. We have been friends for along while, but I've never known he was gay till a few years ago. Anyway he's been really looking attractive to me lately, but the thing is I am not gay. I've always just got off to females, and with women, but he is very hot. I was pretty tired and drunk at his place the other day, so I was staring at his backside while he went in the cupboard to get more tea. He caught me looking and smiled, then asked how I thought of him. Long story short, it was just me and him for tea and the earl grey tea was the least thing on my mind. I think I'm not gay, and I've nothing against gay people, but he wants to have with me now and I am wanting to aswell. I'm quite insecure about this all, so can you please help me? Sorry if this question was long.. but I don't know what to do.