Honestly, everyone should get a pre-nup. I think it makes sense and protects both parties.
I didn't have one but my ex and I were civilized about it and neither of us took advantage of the other. We both did have to make some compromises.
And, actually, with my friend - I think they DID have a pre-nup. But I don't know how good it is and I hope that he stands strong for his rights because I know he is in a lot of emotional pain right now.
The person I feel the worst for, though, is the kid. She finally was in a stable home with a loving father and then had the rug pulled out from under her. Awful.