This is really relevant to a situation of mine with an ex-fiance. Nominated.

My overall interpretation of this piece is that you broke off the relationship even though it hurt you to do so, even though you loved her with all you could... but you had to do it for you because you were being treated unfairly in the relationship.

"What you needed me to give I'll never know
Because you always say I don't know"

^I like this line a lot. I've heard plenty of women say that, even myself at times say "I don't know what I want" ... sometimes it's out of frustration or it's a lie. But this line stood out to me because I could relate.

"It hurt my heart and you know this too
I know I'll always come second for you

I'm tired of the lies and the secrets you hold
This time in my heart I have to let you go"

^ now these few lines, I interpret that maybe she was a cheater... she had another lover... hence the "I'll always come second for you" ...maybe it should be changed "to you" ... I think it would flow better. And then of course the lies and secrets always tie in with an affair of some sort. So, just what I envision when reading this.