If the partner has not adopted the non-biological child, but has essentially functioned as a parent to the child, they can make a case in the courts for being a psychological parent. The courts look at certain factors in determining this, including whether the child was encouraged to view the partner as a parent, or whether the partner took on parenting duties such as taking the child to the doctor.
If the judge agrees that you are, in fact, a psychological parent, you have the same rights and responsibilities as a biological parent or an adoptive parent, meaning that you can file for child custody, parenting time, or child support.
Bari Zell Weinberger is the owner and managing partner of Weinberger Law Group in New Jersey. She is Certified by the Supreme Court of New Jersey as a Matrimonial Law Attorney.