What could she do to shake the misery?

Find another guy and get married. I wonder why girls make this mistake repeatedly. They say marry in haste and repent at leisure. Why do people get married in haste and without giving due thought? Love is no reason to get married. When you fall in love you must ask yourself the question "Could you spend your entire life with this person?" if your heart tells you "yes" then give yourself another 6 months and ask the same question. if the answer is still the same after that, only then go in for marriage. Remember that teh most important person in your life is "YOU yourself." Learn to take care of yourself and rest will follow.

You can't do anything about that. Only time could heal her heart, and perhaps the best thing she could do right now is just do what she loves most, that's the problem with giving up your life for someone, only to realize that they've not given their all to you. It's sad, but she needs to deal with it, there's no turning back and there's nothing she could do but stop being a baby and take things as they are.

She could not find happiness else where because happiness lies with in the person itself. Its her wish only which let her be happy. Good times and bad times are part of life, so accept it & learn from it. But do not hold it. Its totally on her whether she wants to live in the moment or stay in the past. Its the innner strangth which makes us happy, nothing else. So just move on in life.