Dwell well.

People don't often break up because everything is wonderful.
After a breakup, it's normal to temporarily forget the reasons why the relationship wasn't working. That's part of breaking the attachment of the bond that was formed. To move on, don't dwell on nice things that are lost. Dwell instead on nice things that have been gained through the separation...everything good that is in your life today.
~Doe Zantamata