@mommyof3,
One of you will need to establish residence
somewhere in order to be able to file. Wyoming seems reasonable enough as you're already there for 2 months anyway. Ask a Wyoming attorney (initial consultations are often free) to give you information on residency requirements for the state and do what it takes to fulfill them -- even if it means that you stay in Wyoming at a campground or a motel for 4 months (or whatever) while he continues traveling. You are going to have to separate and establish separate households at some point, anyway, so you might as well start now.