Let me get theoretical for a sec. In the military, there's a concept of getting ahead of your enemies decision making cycle. This keeps you in control of the battle.
Right now you're ahead of your wife. She has no idea what to do to regain control of the situation. You have a fleeting moment to solidify this advantage. Use it wisely.
Get a balls to the wall lawyer. Fight for a minimum of joint custody if not full custody for your son. Don't give her jack squat over what you have to in terms of finances/marital assets. Make sure all your credit cards and bank accounts are protected. Don't let her take out "half the money" in your joint account. Take her name off the account if you can, close it if you can't. Send her a check for half, with a copy of the closing statement. She might clean you out...
Then go dark. Let her stew. Let her worry like you have for 3 months. Let her wonder if she's truly lost you. Stay busy. Don't reply to anything that doesn't concern your immediate arrangements with your son. Let the lawyer handle everything else.
And enjoy your weekend. You might get hit by a bus on Monday morning, and the last thing you want to do is spend your final days wondering about this pathetic woman.
