I fucked my twin sister’s boyfriend

Me and my sister are identical twins. If you’re around us enough you can tell us apart but we have a very similar sense of style and often times if you see only one of us it can be hard to figure who is who. We live together and while my sister was out her boyfriend came over. He stepped inside, greeted me with her name and then kissed me. At first I didn’t want to embarrass him and let him come in but soon it snowballed and I realized I couldn’t back out or I’d look like a total weirdo lying to him. He came over ready for sex and the thought of going through with it was too exciting to ignore. I took him into her bedroom and tossed my clothes on the floor and let him suck on my titties and fuck my pussy raw. He said I felt so good today, that I smelled good, and that my pussy was tighter than usual. He was just about to cum and my guilt overtook me. I admitted I was a fraud with his cock still buried deep inside me. Then he gave me this smirk.