Cheating with the same woman..

My husband and I have been together for 9 years now and married for 7. The summer after we first got married I found out that my husband had been having an affair with this woman he met while at the gym. He and her both told me that they only had sex the once and the rest was an emotional relationship but he even went as far as going to her birthday party with his buddies and met her friends. I found out when I was pregnant with our first child and I was absolutely devastated. I wanted so badly to leave but he begged and pleaded and agreed to go to counselling for his issues. He told me he just liked the attention from her. But I couldn’t help but think was I not giving him enough? I was giving him a damn baby and have been nothing but loyal and faithful. Since then things had been perfect! I really thought our relationship couldn’t get any stronger and we worked so hard! Not only did he go to counselling on his own but we also went to couples counselling. Well I was wrong and feel like a fool. I was on his computer just a few hours ago looking up some research for a pilot program I am doing at work and I found a new e mail he created. I couldn’t help but look (I know I shouldn’t have but I couldn’t help it). It turns out he has been talking to this woman and STILL meeting up with her!! I messaged her to find out everything and she told me that 3 years later they ran into each other again and met up a few days after that where he apologized for all he put HER through. They had sex that day and many times since then and he’s now even told her that he loves her. The first time she didn’t know I was pregnant but when I was pregnant with my second he did tell her so she knew!! I’m so torn and not sure what to think. He’s been with her almost just as long as he has me. It’s been going on for 7 fucking years!!!!! And he swears she’s the only one to which I do believe even though why should I? Could it be he’s scared to leave me and our children? It sure as hell seems like he loves her if he could do this for 7 years!! And why go back to HER of all people? If he was a chronic cheater and didn’t love her wouldn’t he just have been with someone else? I truly don’t understand and feel like the past 9 years was a total lie. How could he do this to me and our kids. I’m so embarrassed. I took pictures of the e mails so I could confront him but I don’t even know how right now 😞! I’m so mad, sad and feeling every emotion. Anyone ever experience this? Did counselling again help? Did he leave for the woman? Did you leave? If so how did you go about it?