Confused

Why is this pain
following me
it just wont cease
wont let me be
and the knife in my back
he gave it a twist
left me to die
with cut in my wrist
i loved him so much
more then i can say
and there's nothing he can do
that makes this love go away
and its like I'm addicted
to heartbreak and pain
hating the sunlight
loving the rain
i don't want to walk
in the dark at night
full of this fear
my chest is tight
i long to see him
though he makes me cry
i live to hear his voice
though i want to die
its so confusing
coz he loves her
he took my heart
and treated me like dirt
he treated me badly
and i want him back
i don't care he's mean
and a little bit slack
i know he's unfaithful
i know he don't care
but if he ever needs me
he knows i will be there
i love him more then anything
more then he can see
but i know he loves her
and he won't ever love me