Neji will tell them that their jealousy is unsolicited, and that they’re being silly. Internally, he may find it a little pleasing and flattering, but overall, he’d prefer they not feel that way since it might create some drama in the relationship (even if Neji can be quite the drama queen) He’s the most likely to start an argument about it tbh, refusing to admit that he might have been doing something to make them jealous, instead claiming it’s their own fault for feeling that way

Kankuro takes pride in it, he’d tease his s/o about it as much as he could until they actually snapped. In that case, he’ll take a more subtle, reassuring approach and try to calm them down before getting a little corny and telling them something like “I only have eyes for you” and hoping that it appeases them

Shikamaru thinks it’s pretty annoying. Jealousy just isn’t appealing to him, especially if they nag about it. He’s pretty much going to ignore them or call them dumb if they’re all jealous for no reason. But if they’re more quiet about it, like silently fuming, then he might notice and inquire on it. At least it’s not like they’re blowing up about it. He’s more likely to feel guilty if they’re letting the jealousy fester inside without approaching him about it. He’d feel like a bad boyfriend, and it would be one of those rare times where he stepped up to the plate and went out of his way to pester them about their concerns, not letting them off the hook until they confessed what their problem was