Since married couples generally do not consider adoption a viable option, they will either choose parenting or resort to an abortion. Abortion within a marriage is an unfortunate event which can negatively affect the whole family. A few couples choose not to contracept , trusting God for however many children come along. Very large families can result, but some of these couples have surprisingly few children. Benifits of this type of sexual relationships is that the couples don't have the worry of an unplanned pregnancy.
Marital unfaithfulness is the ultimate act of selfishness.
When one partner is unfaithful, this undermines one of the basic foundations of the marriage. Infidelity is always very painful for everyone, especially the faithful partner. It puts both partners at risk for sexually transmitted disease , one partner by choice and the other unknowingly. Usually there's a great deal of secrecy involved. Infidelity can result in pregnancy involving an outside party.