<human>: Could you distill the essence of the text into 1-3 sentences?

I [24] have been with this person for 5 months.

I came over yesterday after he had surgery on his teeth armed with pudding and movies. I get there and his brothers girlfriend (who does NOT live there - she is there usually 3 days a week) is in her underwear pulled WAY up her butt exposing the whole thing and a bra with her boobs totally out. 

This happens when her boyfriend (who is my boyfriends brother and roommate) is around but she's always at least had an overcoat. 

I was totally shocked and kind of upset. It made me super uncomfortable and I spoke to my boyfriend about it. 

His response was essentially that's how things are so get over it. 

To me it's totally weird that this girl walks around in REALLY skimpy underwear. I really dislike it and maybe I'm overreacting but it's really weird to me that she's like that when it's JUST her and my boyfriend. 

Thoughts/suggestions?
<bot>: boyfriends roommate girlfriend walks around in skimpy underwear when it's just her and my boyfriend. I'm uncomfortable with it, my boyfriend says get over it. Way skimpier than normal bikini, full ass out.