May My Spouse Sell, Refinance, or Mortgage Our Homestead Without My Signature?

No. Pursuant to statute, neither spouse may "convey" the homestead without the other spouse's signature. [1] A "conveyance" includes sale of property as well as mortgaging of the property. [2]. This is true whether or not the other spouse is on the title.

For non-homestead real-estate property, a party may convey his own interest in the property without the other spouse's signature, but such a conveyance is "subject to the rights of the other spouse." So as a practical matter it's hard to see how such a conveyance would ever happen without the other spouse's signature, because any prospective buyer or lender wouldn't be getting clear title in such a transaction. And in any case, such a transaction wouldn't prejudice the interests of the non-signing spouse. [1]

Either party in a marriage may buy real estate without the other party's signature. Hence the saying "One to buy, two to sell."