Thank you for your follow up.
Unfortunately, even though your wife did abandon the marriage, she did not break any law, since she is a parent of your son and there was never an order for legal custody or any court order that would prevent her from moving out of state with your and your wife's child.
So, the situation is legally complex and simply because your wife abandoned the marriage, you would not automatically gain any additional custody rights
to your child and you would want to hire a local family law
attorney in Texas where the child and mother currently reside and the Texas family court will have jurisdiction over the child, so this local attorney can file a Petition to Establish Child Custody
/ Visitation for your son and while you can ask for physical custody of your son, the court will examine all the factors related to you and the mother, the living conditions and ability to spend time with the child and provide proper child care and the judge will make a decision related to establishing custody / visitation based on what will be in the best interest of the minor child.
Once again I am sorry about this difficult situation and I wish you the best of luck!