We declare that God has commanded that the sacred powers of procreation are to be employed only between man and woman, lawfully wedded as husband and wife [and that] the means by which mortal life is created to be divinely appointed. We affirm the sanctity of life and of its importance in God's eternal plan.
Fidelity means being completely faithful to a person, cause or belief. It is shown by someone who acts with continuing loyalty and support. Over time the definition of this word may have stayed the same but it has also been diminished by the standards of the world and has become largely misunderstood. Many now believe that as long as there are no physical sexual acts with another who is not your spouse then there has been no infidelity. Honoring your spouse with complete fidelity is more than just not cheating on them physically.
Pornography is one of the most common forms of infidelity and it has disastrous affects on the reader or watcher. Continuing with this act of infidelity is a poison that seeps into the mind and drives the Holy Spirit away completely. Viewing pornographic material taints the mind and soul and leads them to think as people (or their spouse in particular) as an object to give pleasure instead of a human being, a precious child of God, your eternal companion who you are supposed to love and cherish beyond anything save God alone.
Once the mind has decided that people are objects and it is your right to have whatever pleasure your body desires it isn't very far of a leap to thinking that life itself can be done with as you please. The act of making love turns into a recreational activity rather than a sacred one between a husband and wife. Then an accident happens and a baby comes into the picture. Since life is no longer seen as precious, unless it be your own, abortion becomes your birth-control so that you can continue with your life of pleasure and zero commitment.
Heavenly Father sent us all down here to be born into family units who are to love and cherish each other. Infidelity of any kind goes against His entire eternal plan for His children and He has said that abortion is an abomination. He is not sending His spirit children down to earth to have their lights snuffed out before they can ever take their first breath or step in the world. (Successful Marriages and Families, 6-61; 27-290)