Wife is still in contact with girlfriend who broke us up early on before marriage?

My wife and I have had a turbulent relationship starting in 1995. We were teenagers in high school and it was my first girlfriend ever. about a year into our courtship I find out that she has had an on going affair with a supposed childhood friend. We end up breaking up but later get back together to start over. Soon after out first born son comes into the world and she seems so focused on making things work as a new young family. I was excited about it at first, but also feeling that the change had little to do with her feelings for me and more for the welfare and well being of our son. 15 years later after marriage and 3 children she still is in periodic contact with the supposed ex girlfriend named Vantenaya, even after numerous talks about it and how it makes me feel. She wants me to be faithful and not contact anyone form my past regardless of the instance or intent. However despite promises more than I can even remember, I have knowledge that they are still having phone conversations, exchanging text messages and even have had late night contact face to face. Non of this she denies or is in despute. How much more do I have to put up with this? She wants fairness in the marriage, but this behavior still persists. What is really good?