Is he afraid of his feelings, or is he really not interested?

When I met my closest guy friend, he told me that he wanted to let me know he had no interest in dating me. That's how we became friends, close friends at that. We spent a lot of time together, told each other things that we didn't tell anyone else, I was even told that I was not allowed to date any men, because he was afraid that he wouldn't have my undivided attention. One night, completely unplanned, we both got really drunk out at a bar and ended up sleeping together. Surprisingly, it did not affect our friendship in my mind, and he said he was fine. After that, we spent even more time together.

About a month later, we were out with our friends, and some of our guy friends were hitting on me. He said he didn't like it, that it stressed him out, and he doesn't like stress in his life. Since that moment, he has become a ghost in my life. He rarely speaks to me, and I hardly ever see him. I've called him on it, but he claims to have no idea what I'm talking about.

What's his deal?