He's telling everyone I cheated on him

[Racmactac]

I absolutely did not cheat on him but he has decided that I did and told everyone that I'm a cheat and that's why our relationship ended.

Fails to take responsibility for the actual reason it ended but I guess that makes it easy for him to make himself the victim.

But so pissed off that he has put shit on Facebook and told mutual friends.

Do I do anything? I want to go and tell him what a knob he is for trashing my reputation

Well you've had a lucky escape from a knobhead that's the first thing. Will people actually believe him or has he got form for playing the blame game?
you know you're innocent so just hold your head high. It's gonna be tough but block him and it'll be old news soon. Let him see you moving on and happy, best revenge ever.

What was the actual reason? Did he cheat?

Block/delete him from all forms of social and other media.
Don't explain, don't justify.
Hold your head high - he's the pathetic twat, not you.

Those who matter, won't mind.
Thos who mind don't matter.

You dodged a bullet there by the sounds of it.

I'd put them right personally.

Remain a dignified silence. When people do this it's for a reaction, if people mention it I would laugh politely and shake my head at how ridiculous it is.

When toxic people can no longer control you they will try to control how other people see you. He's clearly toxic and you've dodged a bullet.
Block him and any of his associates who are willing to believe his bullshit.

Maintain* not remain

It's so hard to ignore and block.
He didn't cheat.

I have posted before. Basically my kids hate him because he has slagged their dad off.

Choice between my children and him and they win every time