I'm not sure a prenup would have saved him if he cheated, also I was reading that the prenup doesn't apply after the kids are born. Also sometimes they have a time limit too.
She was involved in some of the reality stuff he did. Not sure if she was involved in his companies though. But if it was a team effort with her helping out with the business, instead of working for herself, then I say half makes sense.
Although I don't think she deserves more than half.