Frenemies for life

It took me a while to see it,
as it has done with most others.
But the people that you meet,
are not your sisters and brothers.
For how could a friend
 not ever really care?
And could they disappear
 when you needed them there?
How does a friend not reach out
to those who they say they care for?
and leave them lying there,
 like driftwood on the shore?
We all serve a purpose
and mine has come to an end.
And I've come to realise
that I was never your best friend.
Insecurity, jealousy
and hissy fits
Your senseless acts
just to get a few kicks
I feel sorry for the next person
 you latch on to and drain of life,
And I'd feel sorry for the man
 that might ever put up with you as his wife.
Now I've served my purpose,
it's time to cut the tie
That you thought you could impose
for us to be Frenemies for Life.