Why does he get jealous if he’s not my boyfriend?

Friend of mine claimed that I was flirting with other guys and giving them the “flirty eyes” at this party that we where at but he wasn’t joking or smiling when he said it
Another time, he found out I went to a bar/club and asked if went home with any guys
And just recently, he asked if I had fun at a party that I went to and when he found out I danced on some guy, he gave me a cold shoulder and started ignoring me

Why does he act jealous? But then not make a move...
Why does he get jealous if he’s not my boyfriend?
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