What rights can you have as a STEP-PARENT to a child that is not even yours???? NONE
It is very rare that a judge would order you some form of a visitation to a child that is not biologically yours. You may have helped raise the child and you may be very attached to the child, but you have no rights to the child.
Your only hope would be that the parents are willing to allow you a form of visitation. Which, if you assisted the father in removing the child from the mother - she will probably be upset about that and not agree. If the father is divorcing you - odds are that he will not agree either.
It's almost a no win situation, which is sad for you and also for the child (especially if you were the primary care giver during your marriage to the child's father).
Sorry if this post seems bleak, but STEP-Parent rights are almost non-existent.
Ambr