One the one hand, It feels so good when someone cares about you and gives you so much attention. You feel so wanted, but then it sends mixed messages because he is already in, from what you can tell, a committed relationship. The weird thing is that you can never really know what’s going on with a person. They may show all the signs of a happy and committed relationship on the surface but that doesn’t mean it’s really the case. Even if he is in a happy relationship with someone else it still doesn’t change the fact that people get bored with the same thing all the time, and also it doesn’t change his attraction to you. On some level he probably knows he knows he can’t have you and that makes him want you even more. Adding alcohol just means he is letting go of his inhibitions.
What do you think you should do at this point? Since you can’t know for certain what he wants, the only thing you can really do is decide on what you want and go from there. Do you want something more? How do feel about yourself? That’s where you really have your power.