Disestablishing legal parentage is very complicated, and you should talk to an attorney.
If a child is born or conceived during a marriage and one of the parties wants the court to conclude that one of the parties is not a biological parent of the child and should be disestablished as (should no longer be) a legal parent of the child, the party can file a Motion to Disestablish Legal Parent. The form, with instructions, is available on the Iowa Judicial Branch website at: https://www.iowacourts.gov/for-the-public/representing-yourself/paternity/.
