Hi, and welcome to the forum.

You're hardly the first to do the six-month-splits in the US - but it would be helpful to know where you are from. The big issue with this type of retirement home thing is what sort of visa to get to allow you multiple entries as you go back and forth. There isn't really a visa designed for this, but it can make a big difference if one partner has US citizenship or if one or both of the foreigners have made frequent trips to the US in the past.

As far as selling the house without difficulty - that's more a factor of the housing market (not good just now) than of your nationality or visa status. But legally, there should be no problem.
Cheers,
Bev