Erstwhile

Erstwhile speaks of former things;

Referring perhaps to bygone days,

Sometime in the past when vanished or extinct.

Time bygone, defunct or departed;

Whilom or quondam more seldom used.

Having expired or departed, become dead or defunct,

I would rather be extant, prospective or future than

Long ago, vanished or gone;

Especially let me not be an erstwhile thought or friend.