Husband grabbed twin sister on accident

My twin sister and I look a lot a like but aren't identical. Our faces are different, and our hair looks different if we dont keep it in a ponytail, but more often than not, my hair is in a ponytail. My husband was sleeping and my sister dropped by for a surprise visit. We were visiting and she asked to use my husbands computer. I was on the couch, she was in his desk chair. I hear our bedroom door open and he comes shuffling out. He grabs a monster from the pantry (weirdo doesnt like cold drinks) then goes to the computer and wraps his hand around her neck and says "you need to come to the room with me now". Sister jumps up and has a shocked face and that's when he realized it wasn't me. I laughed at first but the more I think about, the more I think I'll find it hot to watch him fuck my twin sister. I thought about him doing to her what he usually does to me and it started turning me on. He has always found her attractive, but I dont think she'd be good for it, and I also dont know if I would want to keep it fantasy or actually like to see it happen.