And of course, Natasha told Clint that she was getting the marriage annulled, and Clint believed her, but she never actually did. So Clint married Bobbi believing that he was single. Big surprise when he finds out he wasn't. Then another big surprise when Natasha finds out that the Red Guardian (her first husband) is still alive, so her marriage to Clint wasn't legal, so Clint's marriage to Bobbie was legal.

I don't know where this is coming from.