Keeping X in my Xmas

X is the missing Ex-

Who is absent and withdrawn

Creating the vacuum

Wherefrom reality's torn.

.

Y must the cold ensue

Without the likes of you?

Perhaps the next letter to come

Will bring back the perfect roux.

.

Are Zs a disease

Of sleeping alone

Regretting the past

For a present come home?

.

Your letters had promised

A new year come

My door remains open

To your return, warm.

.

Gone, away, and withdrawn

Are the chilling words I fear

Missing letters' phonetics

That are only spoken here.

.

Filling that vacuum

With letters that spell

One word en route

That Advent foretells.