I know of one sports specific discussion group that has, in the last 8 years, had one girl leave her husband and son to move across the country to be near another member of the group even tho she knew he was living with someone and not interested. After living there for a month or so and realizing that he meant what he said, she committed suicide. A few years later, another couple left their respective spouses and moved in together and later married. All of this from innocent internet chat/discussion.
I think you have to be aware of the temptations on the internet the same as you would anywhere else. The fantasy of anonymity can be dangerous and it could be easy to cross the line.
As far as "cheating" on the internet, I am assuming you have never heard of "net sex". To me, there isn't much difference between that and regular person to person adultry.
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.