Legal Question in Real Estate Law in Illinois

In my opinion, the locks should not be changed without something in writing. That said, these situations inevitably get more complicated over time with questions about the value or equity in the property in relation to payment of the mortgage, payment of property taxes, continued maintenance of the property, ... I suggest that the overall situation be looked at and decisions made now. Ideally, the property ownership should be changed with any outstanding mortgage refinanced, but if that is not realistic then some agreement should be reached. You might think of this as if you are renting from the two of you, who together than should be paying the expenses of the property from that rental income.

Additionally, the form of ownership should be reviewed with thought given to what would happen with the property if something unfortunate were to happen to one of the owners. Often, title is held with survivorship rights, which may no longer suit the situation.

I agree with Mr. Repay. See an attorney. Most "couples" who enter into this situation assume all will go well and have no agreement (in the nature of a partnership....) between them, so there are no written responsibilities and enforcement protocols. If this was an "amicable" breakup then it would be wise to have an agreement now between the two of you as to how to handle ownership, any mortgage, utilities..... When one of several joint owners is the sole occupant, often that sole occupant would pay the others a proportionate share of these costs as "rent" as long as the others contributed to those costs/expenses, and that too would have been or should have been part of that agreement. If it was not amicable it becomes more complicated as it appears your co-owner abandoned (especially if she took all her stuff and stopped contributing....). You may have to consider partition, but that would normally result in a sale of the property, although you may be able to settle to per her out her "half". Lastly, if there is a mortgage, that further complicates things as you would have to refinance on your own, most likely.