Another aspect of the Lord’s instructions is that one who accepts a wife must be a faithful husband and give her full protection. Human society is divided into two classes of men — those who strictly follow the religious principles and those who are devotees. By His personal example, Lord Ramacandra wanted to instruct both of them how to fully adopt the discipline of the religious system and how to be a beloved and dutiful husband. Otherwise He had no reason to undergo apparent tribulations. One who strictly follows religious principles must not neglect to provide all facilities for the complete protection of his wife. There may be some suffering because of this, but one must nevertheless endure it. That is the duty of a faithful husband. By His personal example, Lord Ramacandra demonstrated this duty. Lord Ramacandra could have produced hundreds and thousands of Sitas from His pleasure energy, but just to show the duty of a faithful husband, He not only rescued Sita from the hands of Ravana but also killed Ravana and all the members of his family.
From Srila Prabhupada’s purport to SB 5.19.5