The first time Tony got jealous, he thought he was going insane. Pepper Potts, his PA, had a date. Tony didn't like that for some reason. She'd only been working for him for about a year at that point, and in that time, they developed a routine of sorts. They'd banter, he'd flirt, and she'd dismiss it in her usual professional manner, and then they'd forget about it until about five minutes later. It didn't mean anything. Then why did the thought of her going out on a date with someone else bother him so much?

It didn't make any sense. That really shouldn't surprise him, though, seeing as almost nothing that had to do with his personal assistant made much sense anymore. The only explanation he could think of was that he had feelings for her. (Well, actually, it was JARVIS, when he asked him to do a diagnostic scan, because how he felt when she was around was not normal.) Anyways, that was impossible, because Tony Stark did not do feelings.

And yet she was the exception. She seemed to be the exception to a lot of things that Tony knew, which was driving him a bit insane. But there was no denying what he felt. Tony Stark was jealous. And at the moment he was forced to admit that to himself, Tony decided he didn't like it when Pepper had plans.

The first time Pepper got jealous, she was not expecting it. Not after having showed all of Tony's one night stands to the door for that many years.

Sure there was annoyance when one of them was convinced that they were more than just another one night stand, but that had nothing to do with her feelings for Tony, or what she had dubbed "The Thing."

But there was something about how Natalie Rushman didn't fall for Tony's charms like all the other girls Tony was attracted to.

She wasn't jealous of them because — why should she be? After that one night, they mean nothing to Tony. She didn't envy them at all.

Natalie, however, was not one of those girls. She was the one who had taken Pepper's place as Tony's PA, and she didn't like it one bit.

And when she was forced to admit that to herself, Pepper knew The Thing was getting worse.