How they react to you being jealous…
Jaime – Would find it amusing and would tease you relentlessly about people being unable to resist the Lannister charm. Of course, after a few moments – and realizing how upset you are – Jaime would do his best to reassure you that no one means as much to him as you. Not even Cersei.
Jon – Would be very uncomfortable with you being jealous. He doesn’t think he’s good enough for you ,so you being jealous would confuse him and make him feel as if he had done something wrong and that he wasn’t loving you/showing how important you are to him enough.
Arya – Would roll her eyes and say that you’re being stupid. She’s with you not with whoever made you jealous. She would tell you this several times in between eye rolls and “you’re so stupid for acting like this.”
Tyrion – Wouldn’t know how to react. Like Jon, he doesn’t believe he’s good enough for you, so the fact that you are jealous of other people talking/flirting with him would blow his mind. He would probably just sit/stand around watching you with wide eyes full of fondness.
Robb – Would understand why you’re jealous, smiling sweetly and chuckling as he comforted you. He gets jealous when other guys look at you or talk to you, so he would understand where you’re coming from. Of course, he would still tease you lightly over it.
Missandei – Would be shy with the fact you’re jealous of people talking/flirting with her. Being her, Missandei wouldn’t even notice someone was flirting with her. And the fact you’re jealous over it would make her blush and giggle in embarrassment. It would make her feel good though, she would know how much you care about her.
Margaery – Would tease you like Jaime would with a knowing smirk. She would be flattered that you care enough to be jealous, but would also make sure to show/tell you that you’re the only one for her.
Dany – Would be really sweet about it all, like Robb. Dany would understand that you’re jealous and why you’re feeling this way. She would sit you down and explain to you that no matter what, she’s with you. She would cheer you up with some light teasing, and end it with a light kiss and hand holding.