Brokeback Mountain
I would suggest everyone watch that movie at least once, because it was really well done. A lot of men I know twist in the wind when I suggest they watch it.
It shows that love has no boundaries. All emotional and sexual relationships are complicated for many reasons we don't even look at.
How that particular one got started may have been a tad glammorized, but it still doesn't null the fact that complete lives were overturned by the complicated emotional situation.