Edit: As in jealous of them when they're with people of their preferred gender/s, not jealous of their awesome chess skills or something.
I would take it as "I don't want my partner to be themselves and I want to control them so that they are my personal plaything", but I realised recently that one of my friends means possibly "I love them so much!" when they say it.
2. Would you be upset if your partner wasn't jealous of you?
No, I need to know they care, and would be upset if I left them for someone else or something, but I would like to be secure enough that they aren't jealous most of the time.
3. Do you think that jealousy is immutable? Can a person change their level of jealousy?