Taylor asked a number of questions here: More Questions from a Nurse. Here are more answers:
13. What are the thoughts on infidelity?
Infidelity is destructive to the individuals involved and has a ripple effect on other family members, especially children.
As L. Ron Hubbard says in The Way to Happiness Book, "Unfaithfulness on the part of a sexual partner can heavily reduce one's survival. History and the newspapers carry floods of instances of the violence of human passions aroused by unfaithfulness. 'Guilt' is the milder evil. Jealousy and vengeance are the greater monsters: one never knows when they will cease to sleep."
I would recommend reading Chapter 3 of the book because I would say it accurately describes a Scientologist's view on this subject.