Is he paying support if you terminate visitation .. and I don't know I would think you terminate the support as well. Something to think and find out about .. usually the courts don't like to terminate rights unless it's a situation of abuse and that usually has to be documented.
Carolina: I would seek legal advice on your question: Legal Aid for low income, a family lawyer (if you can afford it or your family can help pay, if needed), ask at your local courthouse or call the nearest Bar Association and get free legal help, if needed. Make sure you are getting child support. Check the child support laws out in your State on the web. Sounds like this woman he is with is very immature telling him to be a dad to her son and to ignore his own child.