These online relationships are a sort of escapism. It's all about living in a fantasy world so you don't have to face a reality that could be pretty grim or isolating. The internet makes it so easy to put on a facade that is the person you want to be rather than the person you really are.
No, I don't think you can be in an online relationship without ever meeting. Pretty much guaranteed one or both parties are hiding something a la Catfish.
Explanation by the tongue makes most things clear, but love unexplained is clearer. ~ Rumi