Getting Sole Custody When the Parents Were Never Married

Attorney Answer

You can ask for sole custody, but understand what you are asking for: New Mexico's general approach starts from joint custody, so sole custody is the harder request, not the default a filing parent gets.

Because you were never married, the first legal question is parentage. The New Mexico Uniform Parentage Act, NMSA 1978, § 40-11A-1 et seq., supplies the procedure for establishing legal parentage where the parents were never married, including acknowledgment of paternity and its rescission under § 40-11A-307. Parentage is the predicate for a custody order — until it is settled, there is nothing for a custody order to allocate.

Custody itself is decided under NMSA 1978, § 40-4-9, which sets the best-interests factors a district court applies. Section 40-4-9.1 is the joint custody provision, and New Mexico's general approach favors joint custody, which means a parent seeking sole custody carries the burden of showing why joint custody would not work. "We do not get along" rarely carries it. Specific, documented facts do: violence, substance abuse, untreated mental illness affecting care, sustained absence, or an inability to communicate at all about the child.

Right now, with no court papers at all, neither of you has an enforceable custody right against the other. That cuts both ways — it feels like an advantage while the child is with you, and it becomes a problem the moment the other parent decides otherwise.

What you can do

1. Check whether the father is named on the birth certificate or signed an acknowledgment of paternity. That tells you whether parentage is already established. 2. File a petition in the district court in your county to establish parentage if needed and to determine custody, timesharing, and support. The self-help center or clerk's office has the forms. 3. Write out, in specifics with dates, why joint legal custody would not serve your daughter. Vague conflict will not overcome the joint custody starting point. 4. Gather records that show the day-to-day reality: who takes her to medical appointments, who is on the school or daycare paperwork, who provides care on which days. 5. Expect to be routed to mediation or a custody evaluation. Prepare for it rather than resisting it — how you present there matters. 6. Until an order exists, do not withhold the child in ways a judge will later read as refusing to co-parent. That is the most common self-inflicted wound in these cases.