What you are feeling right now is infatuation. It is a powerful chemical soup that is at the beginning phase of any relationship (illicit or otherwise.) I think this is likely further complicated by your recovery from cancer. Many people experience major moods swings after conquering "death" in their minds (some experience euphoria, other depression, others vacillate between the two.) There is often an unconscious, but compelling need to grab life with both hands and FEEL more, DO more, etc.
To further complicate matters, your husband was by your side throughout you illness. Whether you realize it or not, you may (unconsciously) associate him with your illness, your fear and a feeling of helplessness. If at times, he wasn't able to handle your illness with grace, you may even have some resentments built up. But even if he was perfectly supportive, a part of you may be rejecting him because he reminds you of illness when all you want to do is feel healthy, strong and feminine/beautiful again. I don't discount the feelings you have, but emotion isn't TRUTH. Emotions are fleeting. I have been totally infatuated with someone and two months later mildly disgusted by them. You need to be VERY, VERY wary of following "your heart" right now. You are in a very vulnerable position and this is a time period a LOT of people make choices they regret for the rest of their lives. I had a situation once - my husband was in a bad place at the time, having recently had his own health scare and in danger of being laid off. His way of staving off depression was the throw himself into hobbies with his guy friends. I tried to be understanding, but as the weeks turned to months I was feeling neglected, pushed aside and rather lonely. One of our friend group wasn't as in to the hobbies and he and I would often end up hanging out together, while the others played. He laughed at my stories, he complimented me, he made me feel good. He was smart, could debate on topics my husband found boring and as time went on I found myself looking forward to seeing him. Dressing up when I knew he'd be there. We never spoke of it, but the chemistry was so clearly there on both sides, our friends started teasing him about following me around like a puppy dog. Before long I found myself FEELING like I was more in love with him than my husband. I talked to my mom about it and she had VERY sage advice. She said, "Maybe you are in love with him, maybe you aren't. Maybe he's better suited to you, maybe he's not. But one thing is for certain - you wouldn't have even noticed him if everything was good between you and your husband. And I know that you will never be able to live with yourself if you do something shady. So focus on figuring out whether your marriage is a good one that is going through a dip and needs some attention - or if it is dead. If it is dead and can't be saved - get out with your dignity." I did what she suggested and discovered that my marriage just needed the time and attention I was putting on the other guy. We blossomed and had another 10 great years until other tragedies befell us - but that's a different story. The point is that once I took my attention off the other guy and focused on reconnecting with my husband in about 2-4 months I wasn't even thinking about the other guy. Because infatuation must be FED. In addition, you have another HUGE issue. Your friend loves his wife and was likely feeling a lot like I was at that point in my life - lonely, disconnected, wanting to be SEEN with fresh eyes. But now that his wife knows he's having to fight for his marriage and he's probably realizing just how much he does love her and just how much he doesn't want to lose her. Please don't make matters worse by trying to mess with that. It would be cruel to EVERYONE (including you because it won't end well for you either.) It's not that the two of you don't have "feelings" - it's that I think those feelings have a lot more to do with what is going on inside each of YOU rather than some deep "soul" connection. I am glad you are in counseling - you need to sort out all these feelings before you make a bigger mess of your life and other people's. You've gone through something (illness) that changed you in deep and profound ways - and you need to sort out how to incorporate those in healthy ways. One last thing - be very careful right now. How you behave over the next few months will likely make or break your marriage. Right now you are very focused on losing this other guy... but I can assure you that if you keep focusing on him, you will lose your husband. We all have our limits, and no one likes being taken for granted or taken advantage of - so he's likely doing some serious soul searching of his own right now. Be sure you don't want this marriage before you throw it away. If you do, I can almost assure you that you will not be starting over with your friend. He's probably doing everything in his power to save his marriage right now. But if you really don't love your husband, you can leave with your dignity and find someone SINGLE to start over with.
BS - Female
Married 27 years, one adult child DD May 2016 “When we are no longer able to change a situation, we are challenged to change ourselves.” - V Frankl