I’m single, last Friday was on a work night out and ended up with me and one male colleague last out, I had missed my last train home and he was staying in a hotel in the city and he offered a couple of times for me to stay on the sofa bed in his room. I was tempted (it was a very expensive taxi ride!) but in the end refused because I didn’t know him well enough to be able to tell whether it was a genuine offer or whether he would have expected more and even if it had have been genuine I think it would have still felt a bit odd and given the wrong impression to anyone who knew as he has a girlfriend. My flatmate when I got home though said she’d have stayed so now am not sure if I was being too cautious.
FWIW this guy has never tried anything or given any impression he was looking to cheat - I think it was probably a genuine offer but even completely platonic sharing would be weird for me if it was my boyfriend and a colleague of his I didn’t know.