INTJs. As far as an MBTI that is most likely to cheat, INTJs are one of them.

Which personality types are most likely to cheat?

In my opinion the types which are the most likely to cheat are xSTPs and ESFxs. ESFJ (females), ESFP (females) and ESTP (males) are extraverted, more sociable so they have better oportunities to find someone to cheat with. They need to be popular so if they dont cheat, they will broke up because of someone another.