Infidelity refers to a breach of trust that occurs in a committed romantic relationship when one partner engages in sexual or romantic behavior with someone outside of the relationship. This behavior can take many forms, such as emotional infidelity (having deep emotional connections with someone other than the partner), physical infidelity (having sexual relationships with someone other than the partner), or cyber infidelity (engaging in online sexual or romantic behavior). Infidelity can cause significant emotional pain and can damage or end a relationship.