[NSFW] What kind of a person never, and I mean never gets jealous?

I have been jealous, when I was younger I was very jealous and yes insecure. I don’t get very jealous now, well only on occasion. But I am asking about a person who never, never gets jealous. For example a boy friend who likes people that flirt with you, or wouldn’t mind seeing you bonk that person? Is that person very “OK” with themselves? so much so that they have surpassed a bit of jealousy? What do they get out of seeing someone have sex with you? (Theoretically speaking).