<human>: Can you summarize the given text in a few sentences?

My GF got some sexy underwear from a guy who I don't know. She said that she also thinks that receiving underwear from a male friend feels a bit awkward, but she likes the underwear. I didn't say anything further to her except that I also think it is very unusual. 

Now I'm confronted with the scenario of her running around in that underwear and every time I see it, it reminds me of that guy, which is a total turn off for me.

Is my behaviour understandable and should I express my concern or should I just keep playing it cool?
<bot>: My GF got some sexy underwear from a guy who I don't know and it reminds me of that guy every time I see them.