Are there any other close people that you don't recognize? Do you recognize all you're family? All of your close friends? Or are there other blanks? I feel like establishing a pattern could be important to tracing the root if it's a psychological problem. If it's just your fiance and dogs it could be a dissociation from home? If you had any really close calls on this deployment - like the "I genuinely don't know if I'm ever going home again" type situations it could be a coping mechanism to detach from the memories of home for a brain that truly thought it was going to die soon - or something of that nature. I'm not a trained psychologist so I have no idea what I'm talking about, but I think you should be focused on the reach of the memory gaps if you want to find the key to unlocking or circumventing them.
The best of luck. Even if you can't refind those memories I hope you can re associate her face with the love of your life
(On a final note, are you becoming more able to recognize her like anyone you meet and get to know? Or are you fundementally not able to pick her face out of a crowd? I feel like that is an important distinction)