Long absent, soon forgotten

Proverbial Meaning: You forget about people when they aren't involved in your life for a long time. 

Literal Origins: People only tend to think of those who they are regularly acquainted with, and even your closest acquaintances pass away from your thoughts when they are absent from your life for a length of time. 

Common Usage: This proverb is virtually unheard of.

Adversely see also: Absence makes the heart grow fonder.