I thought this picture was in one of the Sunday School manuals, but now I can only find it in the June 2006 Liahona.
Principle 3: The ultimate blessings of love and happiness are obtained through the covenant relationship of eternal marriage.
The Lord Jesus Christ is the focal point in a covenant marriage relationship. Please notice how the Savior is positioned at the apex of this triangle, with a woman at the base of one corner and a man at the base of the other corner. Now consider what happens in the relationship between the man and the woman as they individually and steadily “come unto Christ” and strive to be “perfected in Him” (Moro. 10:32). Because of and through the Redeemer, the man and the woman come closer together.
As a husband and wife are each drawn to the Lord (see 3 Ne. 27:14), as they learn to serve and cherish one another, as they share life experiences and grow together and become one, and as they are blessed through the uniting of their distinctive natures, they begin to realize the fulfillment that our Heavenly Father desires for His children. Ultimate happiness, which is the very object of the Father’s plan, is received through the making and honoring of eternal marriage covenants.