The Other Woman

Ever had a situation in which you were just stuck? Stuck. Either way you go things could end up not so good. This is hard to share because honestly this does not match my tough chick exterior but I am in a state of confusion and you guys always advise me so well. So here goes:


Everyone knows that the RA and I split up in May. I just felt it was time for him to go and he did. The first month was okay I spoke of being numb and feeling nothing. I threw myself into a bunch of activities to keep my mind and the kids minds occupied. RA would come visit a few nights a week and that was that. In July the RA was around a lot more and seemed to be showing the first signs of regret that he ever left. He began to speak of missing his home and family so we spent more time together. During this split we had sex several times and he told me that he loved me and missed me when he wasn't there over and over.I never said it back just kept my eyes open and my heart closed. I needed to move on.


This weekend he told me he wanted to come home and be a family.He told me that he had been selfish and realized it. This is a first for him because always in our dealings he had never taken responsibility for our dysfunction. He said he wanted to come clean with me and start over fresh.
In that he told me that he had been having a relationship with another woman while we were separated. I was furious and hurt. He told me that he thought we were really done and he should move on. He and this particular woman sped into a serious relationship in which she relocated from another town to be with him. She knew all about me but did not mind. Anyways he confessed all this to me to tell me he wanted to end things with her and come home. He said that while he tried to move on he just couldn't stop thinking about me.
He confessed it all. Then he placed a call to end things with the other woman. He told her that he could not continue  to see her because he had not gotten over me and he was coming home and whatever they had was over. He made this call separate from me. The girl was crushed and continually called him and begged him for another chance or to sit down and talk things over. Something about that situation struck a chord with me. I realized I was not ready for him to move on with someone else. Do I want to be with him? I'm unsure but I sure as hell cannot stand the thought of him moving on so seriously so quickly. She called and called and called him until I made him answer the phone in front of me. When he did she apparently was headed to my home. She was crying and begging and I felt bad for her. She told him She had  gotten my address and wanted to tell me everything that went on between them. I welcomed her over because I knew that RA was only gonna give me a version in which he looked the best. She decided to turn around and not come but she continually expressed her shock and hurt over the fact hat he had ended things so abruptly with her.
I just sat there listening to the whole thing. Him apologizing and explaining that he could not move on from me and her begging and crying. I was shocked. I always thought there at the end that he was being less than honest but I had no clue he had an actual girlfriend that he was spending time with. I was crushed and I felt stupid. He spent the entire night revealing information to me regarding the relationship. I demanded that at least he give me full disclosure. He also tried to convince me that he had learned a lesson and he just wanted to come home and do right by me and the kids. 
I am stuck. Here is why:
I look at it  two ways:
1- He does love me. Here he had this woman who was willing to change her whole life around for him and relocate so that he could be close to his kids and job. She seemed to really love him. I am a realist. I began to imagine how nice that must have been for him. Just carefree dating and having fun. No kids, no responsibilities no baggage between them. You now how good new love feels. Compared to being with me. There is little fun, lots of responsibility and tons of issues between us. We can barely carry on a conversation without arguing. I had no clue she even existed. She was okay with his situation with me so he could have carried on having the best of both worlds. But he did not. He made a choice and he came clean to both of us and then ended things with her.
Then I feel this way:
2- That bastard! How the hell can he move on so quickly and so seriously after 12 years!! And now he thinks he can just come home and start anew like nothing ever went down?! How the hell can I trust him?
I go back and forth. One minute I feel like he had to go experience this with another woman to realize that the grass is not always greener on the other side and now he realizes how much he loves and needs me in his life. This was just the wake up call he needed. Maybe now he will start acting like a man and be there for his family. Then I feel like I can't trust this dude! He had never let on that he was involved with someone else although I asked him repeatedly. 


I need to say here that I have often after a split between us picked up and started seeing someone else rather quickly. But I always told him about it. So I am more upset that he did not tell me then the fact that he had another woman. 
I am so confused. Hearing another woman on the phone telling him what a great man he is and how blessed she was to have had him in her life  and how much she loved him and would wait was really hard. It was something I've never had to deal with. But when things ended it was clear that she was not done. Even after he told her how he felt and he was coming home to fix things she continually begged him for one more night, or even 5 minutes. She has continued to call/text him since that night.
So here's the dilemma. I have her number, and I also can message her via facebook. I feel as if she and I should have a chat. One to clear up any questions I have and two to let her know that if I decide to let him come home she must back off and move on. I want to make sure he left nothing out and that he has not contacted her since that night. But I also feel like that may not be the best idea. 
Originally I felt horrible for her. Felt like she was a victim of his lies just as I had been but upon closer inspection not so much. She knew about me. I am on his facebook page which is where they reconnected and she knew he stayed at my home often and she also knew that I was in the dark about her. So now I really do not feel so bad for her. It has even been discovered that they started their lil thing while he was still living in my home which is why she quickly relocated to get him outta my house. So I'm kinda irritated with her too. She did not care about me so should I even care about her? Should I forgive him? He did come clean to me and is willing to do whatever to make things better with us. But I just do not want anything to pop up later that should be put to rest now. Should I contact her?