Married woman pursued by married man

I have been hurting all summer, to the point where I am deeply depressed. The depression comes mostly from having to keep a deep dark secret I can't divulge to ANYONE. This is the kind of corner my N has created for me, and still traps me in. I liken it to a mouse trying to get away from a trap, only to have her tail caught over and over.

I met this really charming, handsome man in a running club this summer. I never in my life foresaw what would happen. I have been married to my best friend for almost 10 years, and our busy lives left me vulnerable. One day I get a message from this guy with a random comment just wishing me well. I didn't think anything of it. He was married, and so was I. We both simply had spouses that didn't run. He later asked me to run with him, and I remember in the back of my mind I sensed he was into me, but I ignored my feelings. We ran together and the instant chemistry was there. Something about the way he LOOKED and smiled at me, like I was his entire world. HE showered me with compliments, and made me feel SO amazing. Before we knew it we were messing around like teenagers with NO GUILT. He told me he had NEVER done this before, and I definitely haven't. He said he could not resist me, and somehow I was falling hard.

We never had sex, but we would mostly message each other back and forth pictures, and really explicit sexts. I never even knew what that was before, and here I was. He would ask me for photos, and I obliged. Then he told me we had to cut it off in case his wife found out. He told me he loved her, but wanted both of us. By now I felt this INTENSE hatred towards myself, and a guilt like no other, but I was TOO deeply in love. I was okay with saying "goodbye". He would ignore me for weeks, and then come back into my life like nothing happened. The texts would begin again. He would say he missed me. He would make me feel awesome again. And then the low again of rejection. I didn't get it. I still don't. We never had sex, but one day I ended up giving him a blow job in the back of my car. It was the most disgusting thing I have EVER done. I felt so used, because right after he wanted to leave. I felt used like some low-self esteemed 15 year old, and I am a grown woman with a professional job. Never in my life had I EVER allowed a man to use me like this before.

I try to cut him off because I know my heart can't take it. I was super fit, and I gained weight. I can't even completely avoid him because we have mutual friends who don't know. I was AWOL for a while and I got major wrath because everyone LOVES him. He is super charming, and I know I am the one who will always lose out. He tells me he needs to keep seeing me, and I know it is only for his own evil pleasure of watching me try to run away. I know deep down he doesn't truly love or even want me, and that it is a sick game, and yet I can't quit. =(. Saddest thing I have ever had to deal with in my life. IN addition to hurting my poor husband who doesn't know.