Here is a great resource for NFP. Because George and I are using NFP - Creighton Model - in our marriage, we knew something was developing with my body. What a blessing the church teaching has on sexuality.
"The body, and it alone," John Paul says, "is capable of making visible what is invisible, the spiritual and divine. It was created to transfer into the visible reality of the world, the invisible mystery hidden in God from time immemorial, and thus to be a sign of it" (February 20, 1980).