I've known girls like that. They can't accept that sometimes guys want to do like things for the girls they love. You're better off without her.
And regarding the original question. They just wrote MJ as a bitch because they had to sell the break up. In Kraven's Last Hunt, Pete was missing for weeks, and she still didn't go ballistic. She weathered it. Fuck the marriage, married or not married she can handle sort of thing. Or does she expect Pete to not be able to handle when she's on a location shoot for her modeling or acting? But here, oh no. She's yelling at Pete for RISKING HIS LIFE SAVING OTHER PEOPLE'S, while his face is obviously REFLECTING THAT HE WAS IN DANGER, and HE'S NOT TELLING HER, "Um, HELLO? I look like I went ten rounds with Tyson, here, could you not yell at me and belittle my entire life and the choices I've made trying to make up for my uncle's death until I stop BLEEDING ON THE CARPET, JEEZ!"
There are believable ways to get them to break up without shitting on either of them. This? Not.