I am about to start my divorce my ex is currently in jail and probably will be for five years or more. I was woundering how payments will work with him being in jail or when they will start counting how many months he has not payed.

If you are on state benifits then they will collect child support. Call your state agency and see how that is handles

Not quite.

If he is in jail, he is unable to pay because he is unable to work. Child support is not generally based on assets, either (although are rare exceptions). It is based on monthly income.

He should request a modification immediately so support does not continue to accrue while he is behind bars. Even though he put himself there, it does nobody any good for him to accrue an insurmountable debt while he sits behind bars. He is entitled to a modification to zero, unfortunately. Sorry I don't have better news.

Keep in mind, that I am basing my conclusion on California law. Although I can't imagine any court in the nation ordering child support from an incarcerated individual, you never know in Mississipi. (just joking) You should consult with a Mississippi attorney to be sure.

One more thing. If he does not modify the order to zero based on incarceration, he would be unable to later do it retroactively (in California). Retroactive modifications are barred by statute.

Good luck, but don't hold your breath. You're likely on your own, financially.