Lovely shot!
I feel your pain. I have plenty of pics of my daughter solo, of my wife solo, but together? Nope. I have less pics of her and myself, mostly because I prefer to stay behind the camera.
I partially blame it on owning a 1.6x cropped camera and the 50 f/1.4 being the wides lens I own for portraits. I hear the 35 f/1.4 calling... or the 28 f/1.8... 
BTW. She doesn't look much like her mom, does she?! 

