Interesting thread, as a gay man myself it would be good to compare and contrast experiences. I'd like to expand on a question asked earlier, about roles "who is the man and who is the woman?" gayron36 is welcome to disagree with me here but...
I would characterise the gay world as having no set stereotype for its relationship types. With straight guys, its expected that you find a woman, you have a baby or many together, you settle down, you get married, grow old together. The gay world has no typical "way things are done" as such, so you get a huge variety of all different types of relationship models. For example, most guys in their teens, twenties and even early thirties have an interest in more than one partner. There are exceptions, where they might meet the love of their life, but on the whole, a guy just wants to have some fun in his youth. Straight guys are restricted though - they have to fight their stereotype and pretend that "oh yes babe, your the only one" just to get what he wants. Gay guys don't have that restriction and are free to find others that like to do what they want to do.
I myself am a dom top - I get into that kinky bdsm shit. I wouldn't want a lovey-lovey relationship - and there are guys out there for me just like everyone else though