Is this how close friends behave especially in a platonic friendship?

sounds like someone's interested in you... but if he has a girlfriend, that could be a little tricky. of course, I'm a woman and my best friend is a guy, and we are very affectionate with one another, but we've been that way since the beginning, and over the years, it's never changed. This guy's behavior has changed, so it seems as though he wants the relationship you share to change, too. But the girlfriend bit bothers me. Is he looking for some fun on the side, a way out of somewhere he doesn't want to be anymore, or is he seriously interested in having a relationship with you? Until you know that, I'd tread a little carefully.