The only major roommate situation I've lived in was all male (5 of us, separate bedrooms, one bathroom) for the first year, then one of the guys moved out and his (former) gf moved in instead.
Given 5 adults, none younger than their 20s, one in his 30s, we did okay. The dynamic in the house, generally, was that we were all buddies. When Cheryl moved in, she was a sister. We'd scope out the guys she'd bring home, and she'd do the same with any women
we brought home. She didn't have the best taste in men.
Anyway, the roommates were a sexless relationship, I think in part because we knew her before she moved in. She didn't try any moves on us, and we didn't try any on her.