Answer:
It is cheating; if you are involved in a relationship and you show *unnecessary affection, such as flirting, kissing, or sensual or suggestive touching, or becoming involved sexually with another person other than your partner or spouse is considered cheating, no matter what form it comes in. However, the 'rules' of cheating vary from person to person; for example, some people believe it isn't cheating if you are flirting over the internet, while others believe that groping or touching those other than their partner is fine.
*By this, I mean that the affections are not casual or friendly; hugs and friendly pecks (generally kisses on the cheeks) are fine, while any other gesture that suggests a sexual/emotional bond towards a person other than a spouse or partner.