The two most frequently cited types of infidelity are emotional and physical. Data published in the journal Current Psychology outlines why that is. There is a lot of grey area regarding the definition of emotional infidelity.
It is often thought of as a deep emotional connection, where someone is investing (time, emotion, or love) in someone other than their partner, and it is often secret.
Yet, it is important to consider that almost any behavior that is kept secret could lead to feelings of betrayal.
There is greater agreement on the definition of physical infidelity.
Physical infidelity is often considered to be sexual intercourse outside of the relationship. However, this fails to include other sexual activities. A broader definition of physical infidelity includes, but is not limited to, masturbation in the presence of another, oral sex, sexual play, kissing, flirting, and visiting strip clubs. Some may also consider certain online behavior to be cheating.
Online infidelity can include cybersex, exchanging sexual self-images, online dating, online flirting, and using online pornography. As stated at the beginning of this post, it is important that both you and your partner are on the same page about what you each consider to be infidelity.