Is this cheating?

Thanks to celebrities' recent infidelity epidemic, there's now all sorts of articles justifying the times we've snooped on a significant other's cell phone contact list.

Buzz about "emotional affairs" has also returned to women's magazines.

This Oprah.com article says even though emotional affairs lack physical intimacy, they involve a deeper breach of trust and are therefore most difficult to recover from.

There's something dangerous about relying on someone other than your spouse as your chief confidant. But as the term "emotional affair" takes a more prominent role in the relationship world, it also risks making distrust and paranoia more common.

Is there such thing as an emotional affair? And if it exists, is emotional cheating more or less severe than physical cheating?