If you have the logs for this money extortion this is the smoking gun you need OP.

Go get a very good lawyer now and he will asess how good this is and if its suficient as evidence or if he wants you to sink the fucker deeper in his own shit by askin how much he wants, why he does this etc. The lawyer must be real smart tho and that may cost sum money but there are rewards to this fcourse. Then when you got everything you guys will go to the cops and file a case against your loser ex. Time is important cuz if you do all this and the dumbfuck is aprehended before the video is shared you may very well prevent that since the cops are goin to warn him against doin that. If your lawyer is smart while you are executin this plan against the fuckwad he will buy you sum time by havin you ask the derpsack for extra time to collect the $$$ he wants from you.

There may even be a case to build here against him. He can end up as the bred bitch of jail gangs and even pay you sum damages so thats $$$ for you. Trust me cuz I have done sum questinable things in the past and this here be one of my scenarios. Didnt do webcam tho.