There’s been several interviews with Robert posted after his appearance at Comic-Con. Here is what he had to say about Scarlett’s character Black Widow:
Question: Is there a love triangle between Tony and Pepper, and Tony and the Black Widow (Scarlett Johansson)?
Downey: We essentially started off saying it’s a love triangle, and then we realized that love triangle is done in these superhero movies, all the time. What we wanted to do was something just a little bit freakier than that, and I believe we have succeeded. Black Widow is a great character because she is not what she appears to be. It was a great opportunity. I don’t even know if it’s so much a love triangle. Pepper is exactly what she appears to be, except there’s a lot more going on under the surface, and that’s brought to bear, this time.