Sinner Friend

I hooked up w/ the guy my best friend has been hooking up w/ for the past six months. I hooked up w/ him first, but I still feel like I'm a horrible person. She doesn't know. I lie to her. I love her so much, but I still do it. I don't know why.. I think it's b/c I know I'm a horrible person and I want to confirm that fact. I get drunk. He calls. We hook up. End of story.. I think.