If you are a Twilighter girl who wants to break up with her boyfriend, this is the breakup letter for you. I don't own Twilight (tear) and I am also not responsible for any heartbreak or fights that result from people actually using this template to end relationships. So please don't do it.
Dear (insert soon-to-be ex's name here),
I'm sorry to cut off our relationship so abruptly. I know you have questions, and I wish I could answer them all. Sadly, there are restrictions on how much you are allowed to know.
To put it in simple terms, I have fallen positively, irrevocably in love with someone else. It occurred instantly, and there is no going back. I doubt that you are familiar with the concept of "imprinting," but it is a freak occurrence unique to my race. I may have made it known to you previously that I am 1/16th American Indian. My condition relates back to this lineage – a mysterious trait has manifested itself, and I am powerless to rebel against it.
His name is (insert new BF's name here). That is all I can say.
Again, I am sorry that you had the misfortune of falling for a girl who was already so wrapped up in mystical forces beyond her own control.