Ok, there is so much to address here, but #1 is 'Is there something missing in that particular girl'
... Cheating is not the partner's fault. If it is merely a dating relationship, there is no excuse for being unfaithful. If he needs something that is not being provided in the relationship, he either needs to leave or talk to his girlfriend about the issue. Cheating 'because she's not enough' is complete bullsh*t.
#2 is the repeat offender. No, it's not possible. Whether it's tomorrow, next month, next year, or five years from now (though I'm betting on the faster horses in this race), he's going to cheat. It's not because his girlfriend isn't fulfilling his needs. It's because he's a habitual cheater.
#3 Cheating rule: If he's cheated twice, there's not salvaging the relationship. End of story, no more questions. Once is a mistake he can regret. Twice is intentional and disrespectful beyond all forgiveness. A man that continually cheats thinks little of the women he's attached to and considers her simply something for his own convenience, not a person on her own merit.
To quote Einstein, 'The definition of insanity is doing the same thing over and over again, expecting different results.' He's not going to suddenly change.
Of course, if you want the Rom-com version: Oh, yeah, he'll totally have some life-changing experience this time that will change him forever! *throws glitter in the air*