The act of cheating on a partner and girlfriend.

You cannot cheat on a girlfriend, you only cheat on wives. The act of cheating on a partner is a ‘cheat' only when there is a contract binding both.  Relationship between husband and wife is a contract

, even Heaven recognizes it. But relationship between boyfriend and girlfriend isn't a contract, infact no institution recognizes it. Therefore cheating is identified in a relationship when the husband cheats on his wife or vise versa. But cheating isn't identified in a relationship between a boyfriend and the girlfriend. Based on logistics. 

Based on someone logistic who cited that Dictionary definition of “cheating” is not being faithful to a spouse. So that means that your boyfriend or girlfriend is not your spouse and therefore you are not cheating but messing around. 

Another quoted Biblically saying sex and love is exclusively for married couple and not for boyfriend and girlfriend. So I don’t think it is cheating, you only cheat when you are married and not when you are not, anything else you are doing is called “sleeping around” Based on every logistics.