ugh, just awful. Maybe if you try to think of him as a badly behaved toddler having a tantrum that might help? You know how when little kids have a meltdown and shout that they hate you and kick and scream and everything is your fault? That's how he's behaving. And with a toddler you're firm and have boundaries and ignore the screaming and kicking and wailing. Do that. Stay strong. He's calling you selfish because deep down he knows full well he's the selfish one, it's classic projection.