My spouse and I have been married for about 13yrs,but lived together for about 1yr. We have two boys together I have raised and supported due to he serving prison time for about 10 yrs. We never shared any property together. I have supported myself and children. He lives for a girlfriend now for about 2 1/2 yrs now. He has never paid any support for the boys and doesn't keep jobs long or see my kids period!! Quite the loser! So he wants give up his rights due to his life style and I'm trying to get a divorce now that he agrees with all of this and he obviously wants to give up parental rights to avoid child support. And I frankly don't mind due to his ways of life.
So can any one tell me how we go about it before he changed his mind?! For once he is doing the smart thing for my kids, so please can some one help me?!

See an attorney, I know of no court that will let him sign away his parental rights unless the children are adopted.

He may sign away his rights to custody or visitation, he can not sign away his obligation to pay child support. And you should not let him,

Child support and visitation have nothing to do with each other, he should be paying support even if he has never even seen the children. And for their benefit you should be making him pay though the court and child support enforcement.

If you are married and your husband wants to adopt the child, the court will normally let him sign his obligation of payment away

So if he just wants to get out of paying child support it don't happen

He can't "give up his paternal rights" unless someone else adopts your children. He can choose not to exercise them, i.e. by not having visitation with them. However he has the responsibility to pay child support, whether he wants to or not and whether you want him to or not. You should file a motion with Family Court to get an order of child support established. If he then refuses to pay he could wind up back in jail.