You and your husband need to carefully read the presumed title report and the preliminary title report that you should have received concerning the home before your purchased it through escrow. Assuming you received it carefully read the documents in that if there was a recorded third party wall agreement that you are writing about of record which was recorded on your property it would be listed in the documents. if so, then you would be bound by the third party wall agreement.I suggest that you may want to consult with a real estate attorney further about the matter you are writing about after you have reviewed your purchase agreement file to see if you have the preliminary report and the title report that I have written about.