Katie did this for the money and notoriety(did many know or care who Katie Holmes was previous to this??). She was just known as "Joey" from Dawson's creek. She would have never seen this sort of lifestyle without agreeing to this. She stands to make a ton of cash, as well; something else she would have never seen on her won. You have to admit, she isn't that good an actress.
So, she stays married to the guy for 9 years - never ten

and makes more money than she could have ever made on her own; maybe she'll make a few good movies. She'll be free of this game in her mid 30's, which is still young enough to start a real relationship and marriage. She's Nicole Kidman in the making.