Some vast amount of years ago,
Ere all my youth had vanished from me,
A boy it was my lot to know,
Whom his familiar friends called Tommy.
...
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Not only forever but also sunset, sunrise, nowhere, etc. have by usage become two into one. So, whether it is for ever or forever doesn't make any difference!
Apt title for the story narrated in this poem to say and the credit all goes to the poet indeed!