I just got married in Colorado a few weeks ago. He will only need his passport, nothing else. Also, the cool thing (I think its cool anyway) is that in Colorado a couple can solemnize their own marriage, so you dont have to have a ceremony of any kind if you dont want one. You simply go to the courthouse/clerk & recorders office and ask for a license, fill out a form (or some counties allow you to do it online before hand), then they hand you the certificate which you sign as Bride and Groom and voila! you're married. No need for witnesses, judges, priests, etc. Easy peasy. Good luck to you!