Disability Income - back pay

My ex and I were divorced 5 years ago. We've had several battles over the children, who now (by my "temporary agreement" 2 years ago, after his unrelentless lies, accusations, harassment, brainwashing of the children .. I could go on and on) live with him and his wife, a lawyer, about 1700 miles away in a different state than me. We were divorced in the state I currently live in and this state still has jurisdiction with regard to the children's custody arrangement. I knew that before we were married he received a medical discharge from the USMC. I discovered some time ago that after we were divorced he filed for disability income and received a lump sum of back pay and now receives regular monthly payments. We were married for 14 years. I did not know he was owed disability by the V.A. I believe I'm entitled to 1/2 of the disability income he received for the period of the time we were married. I believe he intentionally waited to file with the V.A. until after the divorce settlement etc. so he wouldn't have to claim or share it. How can I recover what he owes me?

Unless the amount he received was based on a certain amount of dependents and he claimed you as one of the dependents (to get more money), he probably doesn't owe you any of it.