ive got to tell him

i cheated on my bf in the first few days of our relationship. i thought nothing of it for a while, but as time has past, i carnt stop thinking about it. im going to tell him tonight....ive have to, otherwise it will be in the back of my mind and will drive me crazy.
i know it will kill him to know, and i will understand if he never wants to speak to me again, but its somthing i have to do for myself.