I live in the state of TX, my soon to be ex-wife gave birth to my son this past sunday---when can i start my visitation with my son and how old does he have to be for an overnight stay?
You need to go to court and get court ordered visitation.
If your soon to be ex-wife is breast feeding, then visitation will be based on his feeding schedule. One thing about breast feeding -- it is irratic because baby's go through growth spirits. So where baby is the mommy needs to be close in case he gets hungary.
As the child grows, the visits will expand.
In Texas, if she wants to, she can restrict your overnight visits to begin after the child is 3 years old.
Of course, if you are nice to her, then she might agree to allow overnight visits sooner/
I strongly urge you to retain an experienced family law attorney to assist you in setting up your child support and visitiaton.
There is a Standard Possession Order in Texas but it does have many variables that you won't know about unless you have an attorney to assist you.