Friend-Zoned by my GF's Twin Sister

Got a GF named Sarah, I was informed she has a twin sister, we went out to dinner together. Sarah was very pretty but i didn't know if i could ever be sexually attracted to her. Then I met her twin sister and was quickly drawn in when my penis was touched by Sarah's twin sister the difference in how I treated them became apparent. I was very disappointed because of my behavior, stayed with both of them overnight. My GF twin sister wore lingerie and a short skirt to breakfast despite me not liking her skirt. The night before they shared a bed, in the morning I was reassured by my girlfriend that she's not mad at me. They were showering when I got home from work, my girlfriend was by my side but I was staring at her twin sister. I knew I was in the friend zone so i asked Sarah to give me a chance with her twin sister, she laughed and said I should ask her myself. I said hi to her and she immediately said no. My girlfriend knew I was disappointed and tried to console me. I'm going to be staying with her for the rest of the week, she said if i can't see her the way I see her twin sister she'll leave me. She said she can't be with someone who doesn't want us both equally, especially if my only issue with her is that she's not her twin sister. So this coming weekend I'm going to try to get over my issue with my girlfriend, she's not my type but i really love her. My only issue is that I can't help but want her twin sister and having the same problem with my own family for years I can't imagine myself dating someone who isn't a twin. <br><br><br>TLDR: My GF has a twin sister, her twin sister is more my type. I have a fear of dating people who are not attractive to me. My girlfriend is attractive as long as i can get past that she's not her twin sister.