There are three types of affairs: emotional, physical, and sexual.
An emotional affair is when you share a close bond with someone outside of your relationship. This can be platonic or romantic in nature. You may confide in this person about your relationship problems and feel closer to them than you do your partner. An emotional affair can be just as damaging to a relationship as a physical or sexual one.
A physical affair is any type of sexual contact with someone other than your spouse or partner. This includes kissing, touching, and intercourse. A physical affair can be difficult to recover from because it often involves betrayal and deception.
A sexual affair is defined as any type of sexual activity with someone other than your spouse or partner. This could include anything from flirting to intercourse. A sexual affair is often the most difficult to recover from because it usually means that there was a lack of intimacy in the relationship before the affair occurred.