1. It may be that the deed was recorded by the seller or whoever handled the sale. If you or he have the original deed, look to see if it has any recording stamps added by the clerk. Alternatively, you may be able to go online or call the recording office to do a search.
2. A deed does not have to be recorded for title to pass. Recording simply places 3rd parties on notice of the sale. It keeps a seller from later re-selling or mortgaging the property. That bills were sent to him for MF's indicates that the resort was somehow notified and changed its ownership records.
3. If... (a) both names are on the deed, (b) the HOA did not foreclose or take back a deed for non-payment of the fees, and (c) the TS was not dealt with in the divorce decree... then both of you own a 1/2 undivided interest as "tenants in common" and are each responsible for the fees.
I suggest that you and your ex ask managment to take back a deed, and short of that, that you ask him to accept a quitclaim deed to avoid liability for future fees. If he does, both deeds need to be recorded and sent to the resort.