It is stated in the Shastras that having sex with a women older than oneself results in depreciation of life.
But, does anywhere in the scriptures it says that after menopause, a man must avoid sexual intercourse with his wife?
Do the scriptures forbid the couple to engage in conjugal rights, after the wife reaches her menopause?
I don't know if scriptures have an explicit stand on this, but the answer can be both Yes and No, if we go by views of the acharyas.
As per Dharma-Shastras, the wife must be sufficiently younger than her husband. So, if we look at it logically, by the time, a woman reaches her menopause age (which in most cases falls between 45 to 55), the Husband must have crossed the age for Vanaprastha, which is a step towards penance and giving off the grihastha ac, the couple must avoid sex.
As Swami Chandrasekharendra Saraswati says in his lectures -
Kama must be inspired by dharma, that is one must bridle one's passions in one's conjugal life, so that, step by step, the carnal urge will lose its keenness and eventually one will gain mellowness to graduate to sannyasa. That stage, though, comes later. But at first, even now, in the householder's stage of life, the passions have to be curbed, little by little, but not forcibly. In the gurukula the celibate-student is brought under strict discipline. That saves him from being swept away by animal passion.
Though we talk of animal passion, we must note that animals mate only during a particular season. They have the sexual urge only when the female of the species is ready for pregnancy. Man is baser in such matters. Brahmacarya helps to control the carnal urge as it first shows up. Then, in the householder's life, since kama is made subservient to dharma, the passions are kept under check.
Since the major purpose of marriage is the maintenance of society and thus, the Dharma (as Swami Sivananda explains in this article), - which is done via procreation of a good progeny, therefore, having sex after menopause might not be a very nice idea, since one cannot produce offspring after menopause, and sensual pleasure, kaama, etc., needs to be shunned with age, not aggravated.
In the book - Dancing with Siva: Hinduism's Contemporary Catechism by Satguru Sivaya Subramuniyaswami (2003 Edition), the acharya takes an agnostic stand on sexual life of a couple.
Mandala 15: Husband and Wife
Sexual intercourse is a natural reproductive function, a part of the instinctive nature, and its pleasures draw man and woman together that a child may be conceived. It also serves through its intimacy to express and nurture love. It is love which endows sexual intercourse with its higher qualities, transforming it from an animal function to a human fulfillment. Intensely personal matters of sex as they affect the family or individual are not legislated, but left to the judgment of those involved, subject to community laws and customs.
....
It does not exclude or draw harsh conclusions against any part of human nature, though scripture prohibits adultery and forbids abortion except to save a mother's life. Advice in such matters should be sought from parents, elders and spiritual leaders. The only rigid rule is wisdom, guided by tradition and virtue. The Vedas beseech, "May all the divine powers together with the waters join our two hearts in one! May the Messenger, the Creator and holy Obedience unite us." Aum Namah Sivaya.
(page 89)
So, as per the above view, it is left to the couple to decide how they want to regulate their sexual life. If they may choose so, they may indulge in it even after menopause.
