Am I being crazy?

Guys I feel like this guy I've been seeing is being shady with me. We had sex the other night. And the next day we were talking about how many ppl we've been with, etc. I asked him if he's friends with any of the girls he's slept with. He said yes, he's friends with 1. I asked him who is she. And he didn't want to tell me at all. I kinda feel weird bc he's stil friends with her, and I trust him if he says she's just a friend, but like can't he tell me which one of his friends she is? This is someone he has history with and someone he still talks to. So I'd like to know who she is. Am I being crazy?