I kinda understand and validate men getting jealous over other men rather than girls getting jealous of other girls. Please note, I mean this in hetero couples/dynamics.

Because I trust the girlfriend to say no to a man, but I don’t trust the man to accept her no.
I trust the boyfriend to say no to the woman, and I trust that she’ll respect his no.

I’m not saying that all men do it, or that all women are respectful of denials I’m just saying that this is how I view it.