Because they are not strong enough to say what they have in their mind and heart. They try taking help of wine and eliminate the scene in the name of not conscious.
They feel so broken and lonely at once as if they were never like this before. For them, moving on is not such an easy task to accomplish.
They drown themselves in the memories everyday and try doing stupid acts.
Its hard for everyone to move on in their life but becomes very easy if one accepts it by heart and considers it to be an important step to be taken for betterment of every person related to them.