My boyfriends best lesbian friend...confused please help :(

Hello, I have been dating this guy for about a year now and we love each other. He isn't the type to say it often or even openly communicate his feelings for me but I'm content with that. He expresses his feelings in the things he does for me. I'm his first real relationship and he has a lot of female friends. I met all of them so I'm comfortable with that as long as there are no one-on-ones. What has really been bothering me is that he has a best friend who is lesbian. She is pretty much like a guy, though drop dead gorgeous and skinny and tan. My boyfriend says that he thinks of her like one of the guys but then why does he have more then 25 pictures of her in her red stringy bikini on the beach? I'm really uncomfortable, confused and slightly disgusted with that. In fact almost all the pictures on his phone are of those two. He fell in love with her a long time ago, they never dated though, but found out that she is lesbian, he told me he is completely over her. They recently took a week long vacation together and it was just the two of them. He went out of the way to make sure they had separte beds and made sure I was at least a little more comfortable with it (never was). I gues my big problem is that I'm not sure how to handle the bikini pictures of her. It really upsets me, he has maybe one or two of me. Thank you so much!

I wouldn't make a big fuss about it. He's with you. So he choose you! Be grateful