My H an affair for five months with a former employee. I had no idea he was seeing someone else, because he would come home on the weekends from his apartment and we would be a family and H and I would have sex. I thought H was just taking some time off to get his life in order, work on his business and work on our marriage.
Although I hate the fact that he was with another woman, the truth is she helped us both focus on what was important and what we wanted. I could either be angry and divorced (which I did not want) or I could forgive H and work on my marriage. OW was not the cause of our problems, she was a symptom of what was wrong in our relationship. H learned some valuable lessons too. He learned that relationships take work and they need to be a priority. He realized that he had to be honest, trust worthy and committed to our marriage if he was going to be happily married.
I know you are hurting right now, but this is not about you. This is his choice. Don't let your self esteem go down hill because of H's A. Take care of yourself and become the best you possible.
H moved home the night I found out about the affair. He went over to OW home and told her it was over. I could see that H was having a hard time and as a friend I told him that I understood that he was hurting and that he was missing OW and that that was normal. It would take some time to get over the A, as well as deal with the guilt and shame he felt.
Know you are not alone, and that you can make it through this. DBing really works. My thread is in Newcomers and it is entitled Help Need Expert Advice to Deal with H.