By mutual agreement you may have decided between you who wishes to be considered the primary parent. HOWEVER - if there was no custody order, then no legally enforceable "Primary Parent" has been designated by the court. There may be a problem if the self-appointed 'primary parent' wants to leave the state with the child. You both REALLY need to see an attorney before this becomes a VERY bad situation for both of you... and your child.
It would be better if you were married, but there are other, less pleasant ways she can get custody. See related link.
Most states lean toward Joint Legal Custody with primary residential custody
What is the intent and does it involve married or single parents?
If married both do. If not married the mother has it until the father has been to court to establish paternity and filed for visitation or custody. If it's not the parents because the court have found them unfit, it can be a relative or someone else.
Of course. Just because you're married doesn't mean you have to live together.
If the parents have never married and live separately with their own parents, a court would need to decide on custody. Typically, the court will place the child with the mother, but the best interests of the child are primary.
Yes.Yes.Yes.Yes.
no
If you have primary custody you rule the child's life. You're the parent in charge but the other parent may still be entitled visitation.
Fathers are frequently ordered to do so there, despite having primary custody. see link below
By determining that the right of a parent to primary custody of the child supersedes the best interest of the child.
Yes if she could prove that the child is better off in her primary care. If the child is thriving and safe with you, it would be hard for her to prove. But custody can change at anytime so she has the right to file.