Your ability to maintain relationships online can be much easier than in person for many reasons but one of the main ones is due to the collective grouping of like minded individuals the internet allows.
These days there are communities for business professionals, work at home mom, internet marketers, online gamers, cat lovers, dog lovers, ferret lovers, etc etc etc.
Unlike in real life, the internet affords you the ability to find these communities that are all based around similar interests. If your boyfriend or girlfriend doesn't like the things you do or the interests you have, that's OK, you can find a nice community online of people who will affirm what you like and encourage you in it.
From here it is easy to strike up conversations, share interests and begin to foster long time friendship.
Due to the fact that you like this same thing, you have a better understanding of things and it would seem that the relationship is easier to maintain.
I personally belong to a really great online internet marketing community and honestly I have developed some really great friendships, I have shared the ups and downs of life and even have met some of them in person as a result. Most of these people may never know me, but because we come together about Internet Marketing, there are times it is easy to share other things with them, just like friends off-line.