I feel I need to state one thing before I get started. I am in no way saying this is universal. I'm just making observations from my own personal experience that seem to fit within a personality type.
Now that that's out of the way, I've come to think that perhaps INFPs may have a greater tendency than other types to be unfaithful in relationships. I think that may be due to having such a strong extraverted intuition. When you're taking everything in, it may be difficult to commit in the first place, and since INFPs (or at the very least, me), have a tendency to fall in love very quickly, it may lead to a situation where you find yourself in love with more than one person, and, especially considering the fickleness that I think may be inherent in someone with such a strong extraverted intuition, may make one more likely to cheat.
Personally, I've never cheated in a literal sense, but I feel like my heart does tend to wander. While I haven't cheated in body, I feel like I've cheated in spirit countless times. And since I won't technically cheat, and I generally find myself having difficulties initiating a breakup, I either end up doing the next worse thing and manipulating them into breaking up with me, or I do nothing and try to keep the other person out of my head. Either way, I'm left with a crippling sense of loss, either for what could have been, or what I had. It almost makes me thing I'd probably save everyone some pain if I could just bring myself to cheat
Now that that's out of the way, I've come to think that perhaps INFPs may have a greater tendency than other types to be unfaithful in relationships. I think that may be due to having such a strong extraverted intuition. When you're taking everything in, it may be difficult to commit in the first place, and since INFPs (or at the very least, me), have a tendency to fall in love very quickly, it may lead to a situation where you find yourself in love with more than one person, and, especially considering the fickleness that I think may be inherent in someone with such a strong extraverted intuition, may make one more likely to cheat.
Personally, I've never cheated in a literal sense, but I feel like my heart does tend to wander. While I haven't cheated in body, I feel like I've cheated in spirit countless times. And since I won't technically cheat, and I generally find myself having difficulties initiating a breakup, I either end up doing the next worse thing and manipulating them into breaking up with me, or I do nothing and try to keep the other person out of my head. Either way, I'm left with a crippling sense of loss, either for what could have been, or what I had. It almost makes me thing I'd probably save everyone some pain if I could just bring myself to cheat