It means you are really next to something
You are near
The conspirators
in Julius Caesar had to be close
to sink in the knife
the old way of killing

It means, you are with another person
who you really like
who you trust
who you allow to be near
and share your vulnerable self: emotional, physical
because you trust
he would never
sink in a knife

But what happens
if that person you trusted
you lived with, you are close to
becomes a conspirator
and sinks in knife after knife
until you are a heap on the floor
crying out tears, not blood
time and again
ruthless, relentless
until you feel like just a blob of emotion
spreading out like a blood stain on the floor

It's the "unkindest cut of all"
from Brutus
except worse
because a man and wife
are even closer than Julius Caesar and Brutus

That fear in me
Will it ever end?
Will I ever want another man
to be close?