"We do not indeed forbid the union of man and woman, blest by God as the seminary of the human race, and devised for the replenishment of the earth and the furnishing of the world, and therefore permitted, yet singly. For Adam was the one husband of Eve, and Eve his one wife, one woman, one rib."
Tertullian, in "To His Wife", discusses Christian marriage between a man and woman. The need for the institution to procreate and to find...