Property owned prior to marriage normally belongs solely to its existing owner as long as it is kept separate. But when a new spouse starts contributing to the purchase or improvement of the property, ownership issues can get more complicated.

It sounds as though you need a written agreement in which your new spouse agrees to be your tenant in exchange for paying reasonable rent. That agreement could also specifically state that the property is to remain 100% yours. If a significant sum is involved or you anticipate problems, it might be prudent to pay a lawyer for a couple of hours of time to help draft the agreement.