And what, pray tell, did you write that she could be dense enough to think "breakup"?

Maybe she just found the letter and was too lazy to read that much, so she guessed what was inside...

Then that's her problem for being stupid. If I see a note, I'm gonna read it, even if it says "just grabbing coffee, ran out".

My inference is that she didn't actually read the letter, but merely saw it and assumed it was a "Dear John" letter.

Somehow I have the feeling that she was just looking for a excuse to break up

I'm guessing she didn't read the letter, just saw it and assumed it was a breakup letter. Then, working under that assumption, she threw out all your stuff. I'm seeing two very different personalities here.
Yours: thoughtful and loving, the kind of person who takes the time to write a love letter.
Hers: impulsive, spiteful - as evidenced by her throwing out your stuff - when you break up there's no need to pull that nonsense, and angry. Also probably not very invested in the relationship or she would have taken the time to read the letter.
Really sucks that it happened this time of year but it could be for the best

I see I am not needed here anymore. Someone else has already done the right thing. I shall leave now *flies straight up until I leave the screen*

Well said!

Spite.... it’s just a very sad thing to see. Your messing with fire. If she ever feels that you are cheating for some construed reason be prepared to find her and some other dude in your bed.

Omg what did you write or did she not read it????

Dodged a bullet there OP.

Ydi for dating an illiterate!

There's a difference between misunderstanding something and not knowing how to read...

my gf did that before so I dropt every Thing to go to her

rewrite the letter on here so we can read it :)

Did you include "I will always love you" and "I have to go"?

Really? A real breakup letter could be sent in a text with just a few words: Screw you, Karen.