How do You Cope with a Breakup?

Not just any breakup where you didn't really feel anything? One where you fell in love with someone? One where you find out that they fell in love with someone else and you had no idea about it for a while? One where they usually tell you that they want to breakup, but then this time they don't tell you... One where you forgave them for what they did and understand why they did it because of a long distance relationship.. How do you get over it the best you can? How can you move on?