I don't want to be your back-up lover

We used to be the best friends,
Our relationship get closer and closer.
Between lover and best friends.
That makes me confused.
You told me how much I meant for you
Next,You told me how much you love her.
You always call me at night.
You asked me lots of questions how to make her happy.
Do you know what I feel?

Am I your back-up?
I don't want to.
It hurts more than we are just friends.
You treat me so sweet.
As best friend or what?
Suddenly I blame myself why am I so silly.
I try to be cruel to you.
When I heard your voice,I can't.
I try to cut you on phone
When I saw your name,I can't
Because of you,I missed many things.
I wait your call for whole day.
I lost my parents,my friends...

Can you answer me right now?Back-up or what?