Jealousy is a social construct
I was just talking with someone interested in monogamish relationships and the looming specter of Jealousy (insert ghostly "oooOOOOoooOOooo" sound). As far as I can tell, jealousy is an entirely invented social construct. It's like God, in that we all have to pretend to believe in it, and act like we believe in it, when we don't really feel it at all. But we see everyone else acting as if it exists, which convinces us that it is real, and so we have to play along as well or risk being the one weirdo freak. And no one realizes that everyone is faking it.
When I let it go I found that it was complete BS. Maybe it really does exist for some guys? But I think more than anything it's just that we're told over and over "You have to be jealous and beat up anyone who looks at your girl, or you aren't a real man!!" And losing your man cred in this society is fucking TERRIFYING.
I think that's what the real motivator is. Everyone knows the patriarchy is shitty for men as well as women, but they don't mention it too much because it's a lot shittier for women. Well, here's one way it's shitty for men. You have to pretend to be jealous, and bluster about and say you'll attack anyone who touches your mate, because if anyone sees someone other than yourself engaged in sex play with your mate you are automatically less of a man. You lose status, you can't be taken seriously, you are something to be pitied.
Fuck that. I've powered through status-shaming several times already in my life, and every time I've been better, freer, and happier for it. Now I respect people who are in open relationships far more than those still stuck in the social straight-jacket of enforced monogamy. With the limited number of years we have here, why would you do that to your life? It's kinda sad.
And once I let that go, and said "Fuck society, this is bullshit" I actually found that the opposite of jealousy happens. I was happy to see my girl getting that sort of pleasure. Why wouldn't you want to see the person you love happy? And more than that... it was a complete turn on. It's really fucking hot. At least, that's been my experience.