Exodus 19:10-11,15 The Lord said to Moses, “Go to the people, and sanctify them today and tomorrow, and let them wash their garments, and be ready against the third day; for on the third day the Lord will come down in the sight of all the people on Mount Sinai. . . .”
He said to the people, “Be ready by the third day. Don’t have sexual relations with a woman.”

1 Samuel 21:4 The priest answered David, and said, “I have no common bread, but there is holy bread; if only the young men have kept themselves from women.”

Leviticus 15:16 If any man has an emission of semen, then he shall bathe all his flesh in water, and be unclean until the evening.

In other words, if a man ejaculated Saturday night, he could not enter the temple that Sunday.

Leviticus 20:18 If a man lies with a woman having her monthly period, and uncovers her nakedness; he has made naked her fountain, and she has uncovered the fountain of her blood. Both of them shall be cut off from among their people.

Obviously, this created a regular abstinence from sex.

2 Samuel 11:11 Uriah said to David, “The ark, Israel, and Judah, are staying in tents; and my lord Joab and the servants of my lord, are encamped in the open field. Shall I then go into my house to eat and to drink, and to lie with my wife? As you live, and as your soul lives, I will not do this thing!”