In the short view, "custody" is a powerful word that is often described as the objective of a "battle." Let's hope you and your husband can continue to to work on your relationship and your parenting plan, whether your marriage dissolves or not.
You must file a case to confer jurisdiction on the court.
But your trepidation about losing your parental rights strikes me as premature. The court presumes that it is in a child's best interest for custody to be awarded to the primary residential parent. The court is also likely, however, to grant significant periods of parenting time to the so-called "non-custodial" parent.
Without a case file, there is no issue presented and therefore no legal remedy.
I'd suggest that you consider filing a petition for a limited separation. A separation judgment can provide that the separation will expire after a period of time. Then, the parties return to their status as married people unless they decide they'd rather be divorced).
In your situation, you might benefit from a limited separation. This would enable you to ask immediately for temporary orders on parenting time and a limited judgment awarding child support. All other issues could remain dormant as you attempt a reconciliation. There would be no pressure from the court to enter a divorce judgment and your case could easily be dismissed if there were a reconciliation.
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