Sometimes I read through a thread that's been necroed without realising it, and I come across an opinion and think "Wow, this person is absolutely right! They said exactly what I was thinking!" only to realise that it was my own comment from a year ago that I had completely forgotten about. I imagine meeting myself in real life would feel like that. We'd both share the same morals and opinions, which would be great. I also happen to know I am loyal to a fault so we'd be able to reciprocate each other's love without that niggling feeling that the person you love probably doesn't love you as much as you love them. The gay thing isn't really an issue.
If it were just a one-off thing, like getting a limited amount of time to spend with another physical version of myself, I definitely would not spend that time having sex. I'd arrange a two man heist, or use myself to create an alibi while I went and did something else illegal.