Sorry to hear you've had to go through this crap too.
My ex-missus did the same to me with my so called best mate when my boy was about the same age as your kiddie so I know exactly how you feel right now.
As for what to do......
If you want to get drunk, get drunk. If you want to smash a few things, smash a few things.
You'll probably be on auto pilot for the first few days.