Send or nah?

So my ex was an abusive, controlling, manipulative liar. We broke up a year ago n I’ve been w my current guy since. During my 3 yr relationship w my ex tho he’d throw around threats of leaving me when we argued say if I didn’t answer the phone mid fight, and NOW he’s running back to me as I suspected. He’s blocked on everything, so he decided to email. First message was in September, second n third was November and I recently got another a few weeks ago. It’s basically a huge paragraph of him saying sorry over n over right, but I went on his Facebook days before and found out he’s STILL bitching about me to random people and talking to like 6 girls, lying to people about me who don’t even know me, ANYWAY since I found out I REALLY wanna message him back a huge paragraph I’ve already written out basically saying I know what he’s said and he fucked up big time n all this, idk. I don’t care about him but I want him to know he deserves this. I know he wants a reply tho and I don’t wanna give him what he wants but at the end of my message I said im blocking him so I won’t be in contact at all. Idk what to dooooo idec if it’s petty he’s a complete cunt lol