Legal question; but I think it's your mortgage company you really should worry about. If you don't pay the payments, they get to foreclose and there goes your house and your credit. And if you do pay the payments, your "significant other" lives there for free. That doesn't sound like a result you would want. Of course, if there are children involved, that's a whole other matter!!!!!!!!!
Although i am not a lwayer and can not offer legal advise as to be 100% exact, i would think yes. Consult an attorney before you move out. You should be able to get a fre consultation to get the answer your need. Also try your sates bar association web site for FAQ. It may have it in there. Good Luck