Were I you, I would re-think the relationship and how I called it an affair. Being emotionally close to a person is not a crime/affair! Yes, you and your husband do not communicate and the marriage is "dead" and that, too, I think is causing you to err on the side of "it's-all-my-fault"? Your 4-year friend leaving without thinking/caring about you says he was/is not a good friend or any kind of "partner". Partners don't leave each other like that. I would chalk the whole thing up to experience, finish up with your husband and job situation and start your own life with your child.