What is the ruling on a husband singing for his wife or vice versa?

Allah has permitted spouses to enjoy each other in all permissible ways. It is permissible for each of them to look at the entire body of the other with the intention of lawful enjoyment. This includes singing for the other, provided that the singing is free of musical instruments and that its words are good, free from slandering honor, describing women, or discussing acts of worship. It is permissible to express adoration and describe aspects related to them. Also, no one other than them should hear this singing, not even young children, so that no disruption occurs in their upbringing.