I have mediation soon any advice on how to approch my case?

I have physical custody of my child for the last 5 years. Other parent had supervised visits for 2 years due to abuse and for the past two years we have had almost equal parenting times.I agreed to a schedule that other parents attorney came up with .my child lives with me goes to school in my area. Has her doctors in my area. I have provided her with a stable environment. my job has been the same for many years.I am even paying child support to other parent due to the fact that other parent doest have much income so I am required to support my child even when my child is other parents care. Othr parent is seeking sole custody and only wants to allow me to see my child 2 weekends a month. I dont see this happening seeing that there has not been any change in circumstance on either side.