Why?

There are some days where, no matter how hard I try,
it always catches up with me. Even if I smile,
even if I try my hardest to look on the bright side,
the rainclouds will catch up with me one day.
And I will stop, excuse myself from whoever I'm with,
and find a dark corner to collapse in.
and, three minutes or so later,
I run back to people smiling and laughing.
I really wonder what she would make of me now,
Having known me better than anyone ever had,
She was the only one who say through my smiles,
and dragged me off to talk the truth out of me,
and then cry alongside me. She knew me,
but now... No one does, no one dares.
No one will give me a chance,
so I'm stuck here in the corner,
trying not to make a scene.
Even when the tears overwhelm me,
I don't want to inconvenience others.
I guess that is the ultimate truth...
I try to keep my problems to myself,
not trusting anyone to help me.
Too many times, I've lain my heart out,
and watched as someone crushed it.
And I smile at them too, tell them I'm sorry,
that it was my fault it had gone south.
I have a mindset I can't break,
my upbringing told me to protect women,
and so from that evolved my most insidious dogma,
Everything is the man's fault, and his responsibility;
That in exchange for heartbreak, he is supposed to be supportive,
ease the burden from it, make a breakup as seamless as possible,
even if It kills him to do so. 
I help them, they smile at my good sportsmanship,
tell me any girl would be lucky to have me,
and then walk out of my life,
leaving me to cry in the corner.
Life just loves me, doesn't it?
I am the best boyfriend,
for the sheer reason,
that you can pick me up, use me...
and then throw me away...