I’m single, so I can only speak to hypotheticals. It would depend entirely upon who the other person was and what the circumstances were.
Business trip with a person I’ve never heard about or met and all the other rooms are taken? Not great, and I’d prefer if my SO ordered up a folding bed, as those are available at most hotels. If I know the person and have a feel for their character, then it’s decided on that. A woman who treats me disrespectfully and shows no concern for my relationship? I’m going to request that my SO figure out some other sleeping arrangements. A woman I’ve chatted with at company functions and have established some basic acquaintance? I’ll probably sympathize with her about my SO snoring or hogging the covers.
As for wasson’s comparison between sleeping and showering together, well, my response is mostly emotional. For the most part, I wouldn’t have a noticeable problem with my SO sharing a bed to sleep. I would have a large problem with him showering with a straight woman in the average hotel bathroom shower. I’ll try to break it down into something a little more logical:
Everyone has to sleep. It’s a biological function. In the company of others, with few exceptions, we wear clothing when we sleep, and that clothing acts as a physical and social shield. Sleep lasts around eight hours, so it’s unreasonable to expect two people to take turns sleeping. During sleep, the person is unconscious, so no matter what their nefarious purposes, it’s unlikely they’ll act on it.
No one has to shower, though it’s certainly socially preferable. It is not a mandatory biological function. Reasonably, one has to be nude to shower, and that means that is an instant level of intimacy not found in other circumstances. Considering the small space available in an average hotel shower, there is nudity and close proximity. A shower can be completed in ten minutes, so it’s reasonable to expect people to take turns. If two people are sharing a shower, there are limbs and touching and soap, and it would be extremely easy for someone to cross lines of accepted behavior and pass it off as a slip.
As for myself, I expect my SO to be accepting if I choose to spend a night out with the girls, and we happen to crash at one woman’s place, and I share a bed with one of my friends. I can completely understand any discomfort he might feel at the idea of me sharing a bed with a man other than a close relative or gay friend, regardless of sexual orientation. I would respect his feelings and arrange other sleeping quarters. If that weren’t possible, I would come up with something - a bolster placed between us, separate blankets, asking the man in question to speak with my SO (or perhaps the man’s SO?), something - to ease my SO’s worries.
He’d know any good male friends of mine, straight or gay, so I just don’t see him having a reasonable objection. If he had a problem with me, say, taking a nap beside my brother or father, then he’s just going to have to grab his tits and deal.