Monogamy is socially imposed, not a biological prerogative. Therefore yes, cheating is common because social norms can only do so much to override basic human nature.
The natural human relation is a long term partnership without sexual exclusivity, which is common in other primates as well. This is why people cheat but still want to stay with their partners.
I have literally never cheated and have a,ways been in monogamous relationships . But those are the facts.