he might have started to sense the shift in her as she got later into her career then! she started getting involved in missions that were really rough on her (and even now she self medicated in dangerous ways because of it). there might have been a year here and a year there she was completely out of contact, too. she's learned to read and sense a room, and for the most part hide her emotions until she's ready to reveal them, so if he ever took notice she would have probably put a whole galaxy of distance between them for a while.