INFP and jealousy: I don't get jealous very easily. If I do, it's either one of two things: 1- I am feeling insecure or 2- something is going on. My ENFP ex would talk to his ex-gf for hours about sex, and she would tell him all about her current sex life with her new guy. Result: I was jealous and mad. My ENTP ex had a best friend who was a girl, and there was nothing between them sexually - but when she was drunk she would kiss him. Result: I was jealous and mad.
If I sense that someone is trying to play a game with me to get me jealous, then I almost always shut down behind my Te wall and refuse to play. I am not interested in competing for someone. If a guy I am interested in, finds me interesting too, awesome. If not.... not much I can do about it*. (* Other than write horrible poetry secretly dedicated to him as I sob whilst listening to "Pictures of You" by the Cure.)
INFPs and Overprotectiveness: I dunno. I haven't dated since I upgraded my INFP OS to the new 4.0 software. I used to be at times - although I never cared if my guy went out with his friends or talked to them.... too often I was the one trying to push them out the door. "No REALLY go out with your friends!" = "Thank god, a night to myself to cry over some movie wearing grubby pajamas."
ENFJ + INFP: Honestly, I think any type can be with any other type since it's an art not a science. Two of my married friends are ENFJ + INFP. They get along very well but there are definitely a lot of pitfalls that could be "easily" solved. She is always worried he doesn't love her anymore because he doesn't want to spend alone time with her enough, or he doesn't hug her when he first gets home, or he isn't expressive enough.... And I can tell with him he's annoyed that she demands he hug her when he first gets home from work, and that he say ILU in front of a large group of people. I sympathize with both.
For me personally..... I, uh, no. I likes NT types over NF. I need someone who is calm and will help give me a different perspective.... not someone who will cheerfully want to jump off of a cliff with me because I am feeling emo.