I am surprised BA actually did cancel the booking without talking to the OP. In all of my communications with BA they have always maintained that it did not matter who actually paid for the ticket and that any changes/cancellation could only be initiated by the passenger. The OP was as much BA's customer as their ex was...And BA should have sought his consent to cancel or at least re-instate the ticket when it became apparent that such consent was never given in the first place.