Re: what CH just said... if you're here legally, but you don't have a green card, you will need something that the Dept of Homeland Security (formerly the INS - Immigration and Naturalization Service) calls an "advance parole". That is the document that will allow you to reenter the US if you have left the country. It does take a few months to get the advance parole, and that is probably why Clinton's friend can't leave for three to six months.

We've been using an immigration attorney for JtS, and it's been a very complicated process even with the attorney.

On the subject of prenuptual agreements... I believe that a court of law will enforce state laws over a prenup.