(a) Unless otherwise agreed in writing or expressly provided in the order or as provided by Subsection (b), the child support order terminates on:
(1) the marriage of the child;
(2) the removal of the child's disabilities for general purposes;
(3) the death of the child;
(4) a finding by a court that the child:
(A) is 18 years of age or older; and
(B) has failed to comply with the enrollment or attendance requirements described by Section 154.002(a);
(5) the issuance under Section 161.005(h) of an order terminating the parent-child relationship between the obligor and the child based on the results of genetic testing that exclude the obligor as the child's genetic father; or
(6) if the child enlists in the armed forces of the United States, the date on which the child begins active service as defined by 10 U.S.C. Section 101.
(b) Unless a nonparent or agency has been appointed conservator of the child under Chapter 153, the order for current child support, and any provision relating to conservatorship, possession, or access terminates on the marriage or remarriage of the obligor and obligee to each other.