9 Restitution of conjugal rights. When either the husband or the wife has, without reasonable excuse, withdrawn from the society of the other, the aggrieved party may apply, by petition to the district court, for restitution of conjugal rights and the court, on being satisfied of the truth of the statements made in such petition and that there is no legal ground why the application should not be granted, may decree restitution of conjugal rights accordingly. Explanation. Where a question arises whether there has been reasonable excuse for withdrawal from the society, the burden of proving reasonable excuse shall be on the person who has withdrawn from the society.