Unfaithfulness [noun]
Definition of Unfaithfulness:
infidelity
Sentence/Example of Unfaithfulness:
Philip was disgusted with her unfaithfulness to his friend, and that was the reason of his absence.
It was not Audrey's unfaithfulness that had hurt him so much as her untruthfulness.
The system works well, for unfaithfulness is said to be unknown.
For three years my husband disgusted me with his unfaithfulness.
Unfaithfulness and negligence are condemned and punished in both.
May hung her head like one accused of gross unfaithfulness, with some show of reason.
Unfaithfulness in the keeping of an appointment is an act of clear dishonesty.
And she gilds her unfaithfulness, forsooth, with the name of divine charity!
He discovered her unfaithfulness months before he disappeared.
You are only giving this as an excuse for your own unfaithfulness.