Why do I constantly dream about an x of mine after being apart for 11 years?

I had an x named tj. I loved her more than anything in the world, however, she was not that into me. She was more interested in making money, running her rental business, fixing up her house, and djing than spending much quality time with me. When the relationship involved romance and sex, it was 100% complete and like nothing else I had ever shared with another. The problem was that I felt like I loved her so much more than she loved me and I wanted to spend so much more time with her than she wanted to spend with me. After a long period of time and a yo-yo relationship of break ups and getting back together.. I finally had enough and ended the relationship. Once I started seeing someone else tj came back into my life and begged me to get back with her and basically said she understood what I was saying all along and that she would change. The problem was.. I still loved tj so much I could not let go completely but I also got involved and stayed involved with the other woman that I started dating. TJ finally ended it and did not want to be the other women and I completely understood. LM and I have been together for 11 years now and I have not cheated and have been very loyal and happy. I have a great relationship with Lm.. full of fun, excitement, love, respect, harmony, intimatacy but no romance and sex. I am sure alot of relationships are like that after 11 years but my problem is that I dream and have sexual dreams all the time... 11 years later that involve my x TJ. They seem so real and so complete like it was yesterday. I haven't talked to tj in years and have since moved out of state. I don't really want to talk to TJ for fear of it causing problems and distractions in my current relationship with LM. I don't want to leave my current relationship at all.. I am completely happy here at home, however, for years I have not stopped thinking about her or dreaming of her. What do I need to do to get past this?