AE here. I don't post often but my normal screen name has my real name in it, so obviously I cannot use that here.
Huge problem here. I have been with FI for 2 years. We are getting married on Saturday after an 8 month engagement. 2 months ago I went clubbing with FI's younger sister, "Shanna", and a few other girls. FI was out of town for work. Shanna has been a "lipstick lesbian" since her teens. She has also been a model since she was a child. Very, very beautiful girl. Anyway, at the end of the night Shanna and I lost track of the other girls; they ended up all hooking up with ex-boyfriends, friends with benefits, or new guys they met that night. Shanna and I were too drunk to drive the 45 minutes home so we got a hotel room (taxi would cost too much).
The hotel only had rooms with king beds available, so we figured it was no problem. When we got into the room, we both stripped down to our bra and panties since our clothes smelled so smoky from the club, and got into bed. Minutes later, as I was dozing off, I felt Shanna's hand removing the clasp on my bra. Before I realized what was happening, she had removed it and was fondling my breasts. I turned around to ask what she was doing, but she started kissing me and making out with me before I could ask. I was so drunk I just went with it and we ended up having sex. Two or three times that night, I can't remember. What I can remember was that it was amazing and I had never felt that loved and worshipped before. FI goes on long business trips, often international travel, so Shanna and I have been able to spend most nights together, having sex and falling in love. I am absolutely and positively in love with this woman. I have never felt such feelings for another person. That I feel this for a woman is shocking. I have never been bisexual or curious. I had never even kissed a woman before!
FI is coming home from a 2 week business trip tomorrow. We are to be married this Saturday, followed by a 2 week honeymoon in a tropical destination. FI is everything my parents and I dreamed for myself. He makes extremely good money, he bought our 4,000 square foot house himself, I was able to quit my job soon after we became engaged to focus on wedding planning and homemaking, followed by hopefully pregnancy and parenting after the wedding. I have always wanted to be June Cleaver and FI is making this dream a reality for me. I don't know what I would do if these dreams had to vanish. I can't give up FI and this lifestyle but I find it impossible to give up Shanna. She is everything to me and she fills in all the holes (literally and figuratively) FI leaves empty when he goes on his long business trips. I do love him so much, but it is very hard to be alone in our large house when he is gone for so long.
Now here's the second kicker. Shanna has been seriously dating my stepsister, "Emily", for 2 years now. Emily told me last weekend at my bachelorette party that she is going to propose to Shanna the weekend after our wedding. Emily has no idea Shanna and I have been having an affair for 2 months because she has been living 4 hours away for the last 3 months (job transfer). They see each other every 2-3 weeks for a weekend. Obviously Shanna and I don't see each other during these visits. Emily and I became stepsisters when we were young teenagers, so we grew up pretty close to each other. This would devastate her. She has said Shanna is the love of her life and she can't picture being with anyone else. I fear what this could do to our relationship.
What do I do? If I come clean, I'll lose FI and Emily. My parents and FI & Shanna's parents would never look at me and Shanna the same way again. Maybe I would lose Shanna, too, I don't know.