When running around the Legion camp I hear a Legionare say that "the new slave is quite beutiful". I was wondering if he was possibly talking about Boone's wife and if I could find her?

I'm pretty sure it's not Boone's wife. If you talk to Boone and get him to open up to you, he'll say

I had a pretty strong feeling that Boone's wife wasn't going to be found when he seemed to be the only person in town to know where she went, she wasnt coming home and the Legion might be looking for him for revenge. Might not of been in your face obvious, not it wasn't really a secret eigther.

I figured that might be the case, still Bethesda is known for throwing things outta left field in these games so after hearing that Legionare say that I thought it might be possible.