If my ex fails in paying child support so far, can I have his rights revoked soon?

My ex had committed coercive rape and got me pregnant, but I have not yet taken that case to court. He had petitioned for parental rights, in which case I was given sole legal and physical custody. He is to pay 20% child support of every check and I have only received one check in the last month. It has been at least one or two more payment periods. How long do I have to wait until his neglect to pay child support is enough to revoke his parental rights? And if I take the first mentioned case to court, would that have an effect on the matter of revoking his parental rights?