I have only 'divorced' a friend once. We met while sharing a house at uni in the 1990s. It took a long while to get there, but over the years he:
a) Promised me that we could find a houseshare in London after we graduated (we were studying in Leicester). Then moved out and phoned up to tell me that he'd changed his mind and moved in with some other friends instead.
b) During the same conversation told me I could 'whistle' for the share of the final gasbill that he owed (which was in my name, more fool me). At the time I was on JSA and I had to make an agreement with the Gas Board to pay it off at a fiver a fortnight for however many months.
c) Tried it on with a new partner of mine, while I slept obliviously in the next room, saying: "Fuck CharityFunDay, I want you all to myself".
d) Came to visit me in my hometown and called my grandmother a 'boring old bag'.
Those are just the ones that stick in my memory.
The final staw was when I invited him to a work party. He was extraordinarily late, so much so that he was holding things up. I rang to find out where he was and got an earful of abuse for my pains. I hung up. He eventually rolled up without a word of apology and makes himself at home. He starts slagging me off to another friend in attendance, saying: "CharityFunDay could do so much better than this job". Then he got pissed and picked an argument with me. At this point, I had had enough, notwithstanding the fact that as an employee I had to be on my best behaviour. I took him firmly by the elbow, marched him to a waiting limo, shoved him in it, looked him in the eye and said "Goodbye" and meant it. Then I slammed the door shut and off he went. Haven't seen him since.
I sometimes wonder if he ever thinks about me, but I'll never know and I don't really care.
So that is my solution for dealing with selfish cunts. Cut them dead. Don't apologise, don't explain: It's not worth it.