I'm not sure what to think

He made is sound like he had sex with some random (when we were talking about getting together). We just made up a couple days ago. I just found out it actually was a friend of mine. A distant one but still a friend. I understand that he didn't want to say but I'm sad that this is what actually happened.

So my question is did your guy ever have a past that included people you know? Its not sunk in yet. I want to get over it. That is honestly what I want. How do you get over that?