I'll keep this simple,

I have a ex - friend / co worker we used to somewhat hang out, Up untill i left my old job he always hating on my facebook status and talks shit behind my back.

He's always been jealous of me. Due to me picking up more girls / beter gym gains ect. I've always been a good dude to him but i find he just want's to bring me down.

How would you handle this? and what would be your reply on facebook after a smart remark

I would just ignore him.

I would forget about that dongus

thanks guy. I guess it's , my stubbornness i really want to put him in his place. I know deleting him off Facebook would be the best bet.

This.

Remove him from your facebook contacts. No reply is needed.

He's not worth you time and attention. Ignore him
On facebook don't just unfriend him, but block him

Just pay him no attention. Focus on your future