Well done getting this far OP. Look, you know what you need to know. You also know that he will lie and weasel and refuse to be honest with you (probably doesn't know HOW to be honest does he?!)
So - the way to take back the upper hand here is to just dump him, as others have said, and disengage. You won't be missing out on 'closure' - you'll be getting a differnet kind of closure- the satisfaction of looking back and knowing he tried to fuck you around and so you cut him dead. Instead of a big scene and crying which ends the same way as all your other confrontations have done - you frustrated, him smirking inside.
Text something like this:
'Hi X I'm sending this to let you know I'm done with our relationship. Things haven't been good for a while, we're clearly not compatible so I think it's best we both move on. Best wishes, Life'
Him 'Blah blah paranoid you think I'm cheating etc'
You - 'Hi X, I think you've just answered your own question! I'm not sure it's a good idea for anyone to be in a relationship with someone if they consider them paranoid and unreasonable, so looks like I've done you a favour
Have a great life, but please don't contact me again, thanks'
You'll both know the score, and you'll have shown him very clearly that you take no shit and you've dumped his ass and (this is the killer) you're not interested in hearing his bullshit over it any more. Which is pretty much the opposite of paranoid. :)
He won't be able to show those texts to anyone and say 'ooh look, look at nutter woman and what she's done now'. No begging. No accusing. Nothing except 'Ok, go away now, I'm tired of you, you're crap.'