Guy's Behavior

Why doesn’t my crush talk about his girlfriend around me?

I have a crush on this guy I know & way back in December/ January I was talking to a guy & I mentioned it to him after that he mentioned that he started talking to a girl. I thought me & this other guy were gonna start dating but things just didn’t work out & I told my crush that we stopped talking. Fast forward to now. He hasn’t spoken a word about her since that day I told him I was talking to a guy. He talks about her to other people but not me. Everytime he tells me a story that she is in he always refers to her as “some girl“ or “ this girl that was there” never his girlfriend & I know it’s her because our mutual friends have told me the same story & the girl is her. Why wouldn’t he just tell me he has a girlfriend? Why does he never speak about her to me? Why does he never bring her around? Thank you for answering btw!
Why doesn’t my crush talk about his girlfriend around me?
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