Can't make assumptions, Bags some sensitive person might be offended.
A friend of OH's rang merecently to see how I was getting on. He told that he had been at some do or other, and got talking to a stranger who said his partner was busy and could not come. When he asked politely what she (partner) did, the bloke went ballistic at him for assuming that his partner was female.
My answer would have been that statisticaly it would have been more likely to be right than wrong.
When he got home he started thinking seriously about this fracas, and decided that the word "partner" was the trouble, it was not specific enough. So he invented two words to solve the problem "gartner" for a gay partner, and "lartner" for a lesbian one, and is trying to get these adopted. He even wrote to a bishop friend asking him to help. The letter included a humorous aside that you could also replace "spouse with "gouse" or "louse" so I don't think the bishop took it all that seriously.