Just one question. Contraception is practiced to prevent pregnancy. the rhythm method is used to

[rug]

4. No, it's not for procreation only

but the Church's position is that it should always be open to the possibility of life.

The terminology used is that sex should be both uniitive, i.e., expressing the unity of two people, and procreative, i.e. open to the possibility of procreation out of that act of sexual love.

From this view of sexuality stems the whole ball of wax and it shapes the Church's position on extramarital sex, same sex relations, contraception and the rest.

Here's an old statement on it from the US Bishops conference:

http://old.usccb.org/prolife/issues/nfp/Unitive.pdf

It's an interesting point you bring up about those beyond child bearing years. Barring a miracle, procreation is impossible, yet the Church routinely acknowledges and celebrates people married 50 years or more.