How to structure a partnership with other married couples?

[Ryan Evans]

I grew up in Washington State and would love to build a dream cabin in the next couple years out in the mountains. The problem is that what I'm looking for would require a pretty big mortgage. 

Two of my absolute best friends from childhood (whom I've lived with and get along with great) are talking about going in on a cabin for all of us to use and split 3 ways. Aside from all the house rules about usage, bills, pets, family, maintenance, etc., I'm not sure the best way to structure a potential deal. 

The issue is the other two guys are both newly married. Frankly, I'm not sure their marriages will last. If one or both of them gets divorced and their spouses get half of their combined assets, I can imagine it would mean serious complications for the cabin. 

If a divorce happens, I don't want it to have any impact on ownership or rights to the cabin between the three of us guys. Would that require both of the couples getting a postnuptial agreement before buying? Or is there a better way to keep the property between just the three of us and not the five of us.