Who Is Sleeping In My Bed?

After years of marriage
it was bound to happen
someone took my place in bed.
Brought in as a trusted friend
then little by little intruded
on the sanctity of my spot
beside my husband.  

I should have become suspicious 

but it never occurred
and I was taken by surprise
when I walked in and heard
their synchronized breathing
and there he was, the family dog,

asleep on my side of the bed.