I probably would because I don't think it is possible. I don't think "cheating" is just lustful thoughts, and all the internet allows is lustful thoughts.
Cheating, at least to me, implies some sort of physical contact -- the physical as opposed to the fantasy.
Now of course a lot of this internet contact is to set up physcial contact. But the cheating, in my definition, doesn't happen until the physical contact occurs.
Of couse I am merely accepting societal norms for this, which are, of course, arbitrary. In Islamic countries, showing a bit of female ankle is "cheating." See their face, Oh my!!!!
Can a western man and woman kiss without it being cheating? Of course, it happens all the time -- there are lots of social kisses that don't have sexual significance, per se.
Clinton, of course, used a very narrow definiton -- way outside the societal norms. But it is certainly imaginable that some society could somewhere adopt that definition. Just as Islamic societies can't stand the sight of female faces in public, just like we can't stand to see a couple of square inches of their flesh about twelve inches lower.
These are obviously both completely arbitrary designations with no other absolute meaning.
So these concepts, such as "cheating" can mean almost anything to anyone -- I'll keep it at sexual physical contact -- not at mere fantasy, no matter if alone or in conjuction with another communicating human.
Thoughts are private. Communication is the sharing of thoughts, which can be done over the internet. Sharing lustful and intimate thoughts with another person may violate the agreed-upon boundaries of a relationship, at which point it becomes "cheating."
There's also cyber sex, which is very similar to phone sex (it's mutual masturbation while "chatting" with one another). That's more than just having "lustful thoughts," that's acting on them, in a way that's destructive to relationships. And it's cheating.