She struck me as emotionally young, for all her fame & semi-success. Plus, at 28, five years can seem to go by quickly. Especially when your career as a
young star seems to be waning. Those years are crucial for a actress. Tom probably promised he'd make her an A-lister and her career as successful as Nicole's was. He did make 3 movies with Nicole.
While he did make her a
celebrity A-lister, hence, deliberately making their relationship so public and
INVITING all of us into their lives, when previously we couldn't care less. Her career didn't prosper as well. If anything, she ended up NOT reprising her character in
Batman. 
Wasn't that also Sci related? Does anyone remember? I thought she said she wanted to stay home with Suri and study more Sci courses or something like that? Or that the
Batman movie was no longer along the lines of her new current (Sci) beliefs.