There's 2 or 3 pairs of female housemates in our parish that may be now (or may have been in the past) sexually/romantically involved, but I (being generally out of the gossip circuit) would have no idea, and I've been in the parish for 23 years. It's common enough for women to live together; if they don't wear rainbow scarves or entwined female-symbol earrings, most people wouldn't know.
The same may be true of guys too. Males can certainly share an apt without being sexually involved.
I would imaging there's ALWAYS been a lot of "Don't Ask, Don't Tell," simply because people don't stick their noses into other people's household management.