This came to me last night while I was listening to THE most amazing version of Music Of The Night.  It's from Erik's POV, after Christine left with Raoul, abandoning him to his fate.

What Price For Love?

Yes, I admit I deceived you,

But was I really in the wrong?

When I accomplished all I set out to;

Inspiring and encouraging your song.

I assumed the guise of an angel

But was that really so bad?

When my sole source of motivation

Was to save a girl I found melancholy and sad?

If you'd looked at your face in the mirror

And observed the same complexion as me

You'd know why I felt so inspired

To become all you wanted of me

To endure your sadness any longer,

Was more than even I could stand

And so I devoted my time

And plotted and schemed and planned

But when I started to gain your confidence

And you gave yourself over to me

The lies became easier to believe

And to maintain them was all I could see

I should have told the truth sooner

Looking back, this I do realise

But then you'd have seen a true monster

To fear and to loathe and despise

Whatever you see on the surface

Will never be reflected inside

But this face is my curse and my prison

And the reason that I am denied

But, for my deceit I will pay forever

And I know it's a high price to pay

For you have forsaken me for another

When I gave you the free chance to stay

And my world was cast into darkness

With no muse, no music, no song

No heavenly voice to uplift me,

So, yes, my deceit was definitely wrong