Twilight fans: what would edward and bella fight about?

I am working on a fanfic that involves Edward and Bella as humans, already married and they have this huge horrible fight. But I can't think of what they should be fighting about. It needs to be kind of serious, not just a you-forgot-to-do-the-laundry...

type thing. But no cheating or something like that. I just can't think of a serious fight they would have that would leave them both fuming. I'm talking about something that would make a person question the success of their marriage (a little). And they both have to have a valid reason for being mad at the other one. It can't be a one-sided thing. Any ideas?

there are already twilight books made thats like taking stephanie's ideas dont copy her its illegal. !!

Maybe bella spending too much time with Jacob?

I am a super huge fan of the Twilight series. Maybe Edward gets mad at Jacob and tries 2 kill him. Bella wouldn't b very happy.

maybee Edward doesn't like Renesmee spending time with Jacob, but Bella doesn't see what's wrong with it.

They should fight about what real couples fight about: Edward leaving his laundry laying around, Bella forgets to tell him she made plans for them to visit someone he doesn't like, all couples fight over money, things like that would be amusing.