Pepper Potts has been a mainstay of the last three Iron Man movies, but she only made a brief appearance in the first Avengers movie, isn't expected to appear in Avengers: Age of Ultron at all, and was on rocky terms with Tony Stark for much of Iron Man 3 thanks to his various personal issues. Her lack of appearance in Age of Ultron and the turbulent nature of her relationship with Stark in Iron Man 3 in particular would suggest that - much like in the comics, where he is a regular womaniser - Stark will have a new girlfriend by the time the next Iron Man movie happens (the fact he seemed to devote himself to Potts at the climax of that movie means nothing really). Gwyneth Paltrow has reportedly wanted out of the Marvel Cinematic Universe for some time and, given that the as yet unnamed doctor/scientist character played by Claudia Kim in Age of Ultron is set to be "friends with Tony Stark", it seems likely that Stark will have moved on to another woman come Iron Man 4 (because we all know Stark is completely incapable of solely being "friends" with attractive women).
