Is he talking about private matters with her? Your private matters? That’s not cool and I think young people today often overcommunicate. If you haven’t established that boundary with him – do so now. And if he continues to cross that boundary, then that might be a deal breaker for you – and that’s ok.
And sometimes people only want what they can’t have because they are immature or need to feel validated. I dated a guy that had a crush on someone else. She had slept with all of his friends but not him. As soon as we became serious, she moved in. And I moved on. I don’t need that shit.