<human>: Very simple. My girlfriend is 19, we've been dating for 6 months. Its been great. She's bisexual and I'm straight and she's slept with a girl in the past but that never bothered me. Lets call this girl she slept with Sarah, although they slept together, my gf is still good friends with Sarah today. But recently...last couple weeks, Sarah's been sending my GF nudes of herself. 

My GF wasn't sure how to respond and she told me about this. I brushed it aside but she told me again today and it bothers me a little. What's a logical solution to this? Is it natural for me to be bothered by this? How is it any different from a guy sending nudes to my girlfriend, she's bi, therefore isn't it the same as your girlfriend getting snaps from a nude male friend of hers? Help!

Give me the gist of the text in a nutshell
<bot>: GF is bi and she slept with her best friend 9 months ago. Best friend of GF now sends GF nudes of herself multiple times a week. I'm confused how to react/feel. Help.