I'm gay.
First: Gay relationships seems to last longer, because when you finally find someone who share your sexual attractions, you want to keep them. Being heterosexual is like easymode sexuality. There are lots of people who share your sexuality.
As a gay person, when you finally find a person in real life, next step is the fact that they have to be 1) Gay 2) Attracting 3) Likeable 4) Relationship material. Since this isn't something that happens very often, since statisticly 10 people out of 150 will be gay, when you finally find a combination of the four traits, you want to cling on to them. Fighting over the dishes or laundry suddenly don't become worth it, compared to the amount of work and time it took to find them in the first place.
I am not saying that heteroseuxals do not at least try to get it to work, but I do think that some heteroseuxals take their selection of wares for granted, when they consider their own personal feelings toward a partner. "I can just get a new one". Many pop culture songs actually endorses this way of thought, and I think that it's worth considering, that gay relationships are harder to get into, simply because there necssesarily aren't an abundance of gay people around in your daily life.
I like my sexuality, but I think you should appreciate your own aswell. If you like men - and like being a woman, you should stay with that. The grass might seem greener on the other side, but you forget the downsides of having to be called sick, perverted, ******, sinner, moral decay, second grade citizen and nazi on a regular basis by the viewers and writers of FOX News and Conservative media around the world. As a gay guy/girl, you lose the title of "human" in some peoples eyes.