WTF Moment - What are you wearing?

At no point in time should I feel uncomfortable in my own house.  The house is my zone.  I came home Tuesday night after work and the nephew's girlfriend was in the living room on the couch watching TV.  I spoke and went about my business as usual.  A little while later, I went back to her so I could inform her about making sure the nephew put a copy of the updated car insurance in his vehicle.  It was at this point in time when I noticed what she was wearing.  She had on a pair of boxers and a tshirt with the sleeves and sides removed.  The shirt was basically like a cape covering her back and front.  What it didn't cover was the side view.  I had full view of her breast from the side.  What the fuck?  Who does that?  Yes, I am married and have 3 girls.  I just don't have the desire to see the titties of my nephew's girlfriend cause she is hot.