Hooked up with a guy why did he get distant?

So i hooked up with this guy i’ve been knowing from college for a while. We were pretty decent friends. We hooked up & everything seemed great, we talked for hours after & watched movies. He even got super vulnerable & apologized about it. He also asked would I be down to do it again & I was like yeah. Then after that he just got super distant & we’re not even friends anymore.
Hooked up with a guy why did he get distant?
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