Life often imitates art but not in the way we could have hoped. In the case of Scarlett Johansson, it sounds like art imitated art for her in a very bad way on the set of Avengers: Infinity War. She spoke to Bravo TV about being on set and her characters relationship with Bruce Banner (Mark Ruffalo) came up:
"I just finished Avengers: Infinity War. The first one. My character has this ongoing relationship with Mark Ruffalo's character. I had such devastation that day. I don't know why. I was so devastated. It was something about this character that Mark plays, and this is something that should feel so solid and suddenly doesn't or there's… And it reminded me of so much of the things going on in my own life at the time…"
Johansson has recently filed for divorce from her husband and the two of them are in the middle of a bitter custody fight over their 3-year-old daughter. The deterioration of a relationship that should feel solid falling apart is not a fun thing to go through.
The relationship between Natasha and Bruce in Avengers: Age of Ultron wasn't beloved among fans but considering the timeline it would make sense that one or both of them have moved on. They weren't that far into their relationship in Age of Ultron, and in Captain America: Civil War we find out its been a year since they've seen Bruce. Avengers: Infinity War will take place two years after that. While we know Bruce is on Sakaar fighting from Thor: Ragnarok, that's a long time to be isolated. If their relationship is reminding Johansson of her own, then it's not likely we're going to see a happy ending for these two.
Avengers: Infinity War, directed by Anthony and Joe Russo, stars Robert Downey Jr., Josh Brolin, Mark Ruffalo, Tom Hiddleston, Chris Evans, Chris Hemsworth, Jeremy Renner, Chris Pratt, Elizabeth Olsen, Sebastian Stan, Benedict Cumberbatch, Paul Bettany, Samuel L. Jackson, Cobie Smulders, Benedict Wong, Zoe Saldana, Karen Gillan, Vin Diesel, Dave Bautista, Pom Klementieff, Scarlett Johansson, Tom Holland, and Anthony Mackie. It will be released on May 4th, 2018.