Finding a love letter

I found out that the number I was searching for was the woman that he had lived with during the 9-10 months we were apart. She couldn't fathom that he would want to come back to his family. He up and left her to get back with me again, and he told me that they were not together...what a dummy I was for believing that he wanted to be with me and our daughter. He left her, explained to her that he wanted his family back, but she wasn't believing him. I told myself that if he kept on telling her, that she would eventually give up on him. Not so. He had purchased a local post office box while we were apart and I finally got a key to it, right after we moved into the new house. One day, I went to check the mail there. Low and behold, there was a letter from HER. I got her address !!!! I was very nervous opening up that letter. I know, I shouldn't have invaded his space, but I had HAD enough of this lady. The letter was in spanish and I understood most of it, but had to ask around to some of my friends what some of it meant, without giving them the hint as to what was going on. After all, they would have been terribly shocked as well, especially since he made such a big deal of our getting back together again and making things work. The letter basically said that she missed him and she would wait until forever, until he was ready to come back to her. What? What did that mean, that he was going to be with me until things calmed down and then start back up with her? She also gave reference to the fact that he better hide the key to the post office box because she didn't want to call him that much since I was becoming suspicious of the private calls. She also told him to try his best to be around me since I was a witch. Ok??? I wondered why would he want to TRY his best to be around me, if HE was the one wanting to be with me in the first place. Her words sounded to me like he was only with me to get his family back, that then wait until things were calm so he could get back with her again. I was hurt beyond belief, and I knew I had to keep my mouth quiet about the letter, and I had to figure out what was going on. I called my mother and dad who a year before had moved back home which was about 1200 miles away. All I could do was cry.