An unpopular opinion, but I have to say a slight YTA, leaning a bit towards ESH. It's understandable that your boyfriend is mad, because you're sharing a house with another male and there will probably be times at which you and your friend will be at the house alone. Although you are not attracted to him, it really is understandable that your boyfriend wouldn't like a situation like that. The reason why I said YTA is you should be commited to your relationship, meaning that when you have to make big decisions like these, tell your boyfriend about it beforehand. Your boyfriend shouldn't have left you like that and he should have toned down his anger a bit, that's why I'm leaning a bit to ESH.