Sex Guilt is killing

I had sex with my bff's brother! I honestly didn't think it would ever happen I had a crush on him a couple years ago. So here's how it all went down. 3 days ago [Ashley] went to rent a movie and [shane] stayed to keep me company so I droppedy phone and bent over to pick it up and caught him checking me out. I quickly stood upright and sat down. He sat next to me and started complaining how his gf cheated on him for the 3 time, I felt bad for him so I gave him a hug then he kissed me. I'd didn't pull away until I realized what had happened. I was so shocked. He told me that he had always loved me and well you know how it goes we had sex. The only thing I regret is not telling [Ashley] and loving the sex. Am I a bad person for loving the sex???