New Roommates

Okay, recently my boyfriend and I moved in with his friend, because our last roommates (well his best friends wife) kept stealing out of our room. Even after confronted multiple times. Anyways, since we moved in, I've been picking up some sort of vibe from his friend. He would knock on our door to talk to us, but most of his attention would be on talking to me. And my boyfriend leaves to work out of state a lot. Well yesterday he (the roommate) texts me asking for something and I'm like sure I have it.. I open the door.. and he has on no pants ...! I'm like .. is this weird? Or maybe he's just comfortable? I'm trying to not make anything uncomfortable it is his home, but would anyone feel weird by this?