Some basic principles from the Compendium of the Catechism (337-338):

• What is the plan of God regarding man and woman?
  • God who is love and who created man and woman for love has called them to love. By creating man and woman he called them to an intimate communion of life and of love in marriage: “So that they are no longer two, but one flesh” (Matthew 19:6). God said to them in blessing “Be fruitful and multiply” (Genesis 1:28).

 

• For what ends has God instituted Matrimony?
  • The marital union of man and woman, which is founded and endowed with its own proper laws by the Creator, is by its very nature ordered to the communion and good of the couple and to the generation and education of children. According to the original divine plan this conjugal union is indissoluble, as Jesus Christ affirmed: “What God has joined together, let no man put asunder” (Mark 10:9).

Natural Family Planning (NFP) methods provide married couples with the means of achieving or avoiding pregnancy based on natural signs of fertility, in a manner that is environmentally safe, respectful of the bodily integrity of spouses, and  compatible with Catholic moral teaching and the dignity of the human person. 

Here are two helpful groups that assist couples in living out the call to marriage and sexuality that is free, faithful, total and forever:

• One More Soul Apostolate
• Couple to Couple League

There are a few key N.F.P. methods to choose from; please feel free to research them starting with the links below and find what works best for you and your family.

• Billings Ovulation Method
• Serena: Sympto-Thermal Method 
• Marquette Method 
• Creighton Model Fertility Care System 

Finally, here are a few helpful videos from Ascension Press that discuss Catholic teaching marital love and contraception, and why it provides the best foundation for marital happiness and healthy sexuality, even though it requires sacrifice.  May they inspire you.