1 Corinthians 7:3 (NLT)
³ The husband should fulfill his wife’s sexual needs, and the wife should fulfill her husband’s needs.

1 Corinthians 7:5 (NLT)
⁵ Do not deprive each other of sexual relations, unless you both agree to refrain from sexual intimacy for a limited time so you can give yourselves more completely to prayer. Afterward, you should come together again so that Satan won’t be able to tempt you because of your lack of self-control.

Couples need to understand that God made them sexual beings to enhance the intimacy of their bond.  While passion may wane with age, it does not end and couples that set their sexual bond to the side weaken their relationship.  For heaven's sake, don't use it as a weapon for control.  This is your act of grace toward them and their fulfillment of your needs.  Treat it right.  Take you time.  Enjoy it.  Regularly.