If you don't have much earning potential, why you bother a pre-nup. I look it this way, a living will and potential pre-nup (or post-nup) are necessary for kids.
the girl is a nut. It is better they didn't get married. you can argue: the guy didn't love her enough. Based on the same argument, the girl didn't love him, neither. So, it is better to go apart.