i can't have you in my life because "i don't know what i was thinking at the time, i was doing so many drugs and drinking so much" is not a real apology.
a real apology would have been, "i'm sorry that i stayed friends with someone who sexually assaulted you. i'm sorry that i put you in the position of having to interact with this person repeatedly over the last four years. i'm sorry i didn't take your trauma seriously."
without these words, our relationship will never heal, but the hardest part is that you don't even care to try.