Man you guys are being hard on this poor guy! I've been through a lot of similar situations, staying with gay dudes that even KNEW I was straight just hoping that I'd change my mind...or something, IDK....
Being on drugs, particularly meth, leads to some weird shit happening with living situations....The guy is being cool giving you a place to stay and if it makes you uncomfortable, find another arrangement....
When you have no choice and you're using drugs....give the poor guy a pass on not making mature, well though out decisions.....
I've let people stay with me under weird circumstances knowing it wasn't the best idea and I've done the same thing.....as long as you help somebody else out in the future and you're paying off your karma, I just kinda think it's par for the course!
You could tell the guy, "Look, I'm not gay and I have no interest in engaging in sexual acts with men! I am in a bind right now and I need a place to stay, so if you could help me out for a little while until I sort things out I'd appreciate it..."
That's what I would do.....otherwise, just deal with being hit on everyday! This is a situation a lot of drug-users have been through.....
BTW, there's definitely a lot of gay dudes who have money who look for vulnerable young men to take advantage of....It's pretty common actually, so give poor D's a break! He's doin the best with the hand he was dealt at this point!