I just want to borrow him for 15 minutes. A gay man, to paraphrase Rick's description of Captain Renault in Casablanca , is a man like any other man, only more so. Straight men aren't innately better at resisting temptation. They just have far less placed in their paths. And when they yield to it, their wives often punish them severely for it.
Men dread having to pay to raise another man's child.
Wives, in turn, insist upon a husband's emotional fidelity so they can be sure he'll support their children. For two gay men sharing an apartment, however, these primal motivations toward sexual envy are moot. Further, sexual boredom generally sets in faster for two gays living together than for a husband and wife. That's because very few people are narcissists. Everybody lusts for somebody different.