Can someone who was unfaithful during the dating relationship, be faithful after marriage?

What are the odds of someone being faithful during marriage, if they were unfaithful while dating the person they eventually married? He says that marriage is “different” and the ultimate committment…and claims that he will be loyal during marriage? Can being married actually change somone and rid them of the desire to cheat, especially if he once chose to keep the cheating a secret from his partner?