No marriage between relatives within the prohibited degrees or between or with persons under the prohibited ages shall be declared void except by a decree of the district court upon proper proceedings. A cause of action may be instituted by the minor, by next friend, by either parent or legal guardian of the minor or by the district attorney. In the case of minors, no party to the marriage who may be over the prohibited age shall be allowed to apply for or obtain a decree of the court declaring the marriage void; but the minor may do so, and the court may, in its discretion, grant alimony until the minor becomes of age or remarries. If the parties should live together until they arrive at the age under which marriage is permitted by statute, then the marriage shall be deemed legal and binding.