This letter is from Blaine to Kurt. It will never ever reach Kurt but it's a way for Blaine to express his feelings to Kurt and pour his heart out. It happens around episode 5 of season 4? Yeah. Around there... (Just treat it like he's writing in a diary or something but it's addressed to Kurt - ... I don't think that made sense but here it is!)

Dear Kurt,

I'm sorry. That's all I can say now. I know you'll never ever forgive me for what I've done. But that's all I can say now.

You. You were the best thing in my life. Well, you still are, but you know what I mean. What I did. It's unforgivable. I broke your trust in me. That wholehearted love you had for me. I'm hoping for the best but if you don't ever forgive me, I know I can't do anything and I'll... I'll understand.

To tell the truth, I know that sorry doesn't even cut it for what I did. Even thinking about what I did to you makes me want to do something to myself.

That night we broke up; I saw it in your eyes. I had broken you. People say that the eyes are the windows to your heart. When I looked in them that night. I saw it broken. Saw it broken to bits.

I tried to sing 'Hopelessly Devoted To You' today as my audition song for our production of Grease. But I couldn't do it. I couldn't sing it without thinking about you. Thinking about how I hurt you and that look in your eyes made me break down. I never knew heartbreaks could hurt so much but... now I do.

I've never wanted much. But if I could, I wish. I wish I had a time machine. I wish we could go back to before I cheated. To before life became complicated. To before we started becoming distant. Sometimes, I wish we were back in high school or something. Where I was yours, and you were still mine.

I love you.

I'm sorry.

Love,

Blaine