This is because the habitual residence of the child determines where the proper jurisdiction shall be. (divorce-canada.ca)
Physical custody may call for one parent's home to be the primary residence of the child while the other parent is granted ample visitation. (ourfamilywizard.com)
If your child is still a dependent and your former spouse / partner has primary physical residence of the child then you will have to pay child support. (separation.ca)