What a mess. At this point the only winners may be the lawyers if you go the legal route.

As you both now have dirty hands (extortion and perjury) going into court, it's a toss up who could win. If you lose, you may be on the hook for his legal fees, as well as your own.

He may have a right to the 17000 back (or at least feel that he does), as you accepted it as "payment in full" so to speak. You then changed your mind, and tried to get more. You no longer considered it payment in full, so that deal may be considered null and void.

Your ex demanding the 17000 back probably isn't extortion, as he feels he has a right to it back so it can be settled legally. Threatening for money owed may not be considered extortion.

At this point, why not ask him if you can call a truce. You will sign a letter stating money received completes divorce financial requirements (you will not try to get more money), and he will sign a letter not to have charges pressed against you.

All money that has changed hands at this point stays with the person who has it, and you both agree not to go after the other for any reason based on the current information you both have at this time.

Using this site for any reason such as to prove dates he knew about inheritance is simply a bad bad idea. There is a treasure trove of information for them to glean and then be retold thru his perception, which will probably be very different than yours. There could be extremely private information that you never intended for him to know about. You could be handing him a hammer to clobber you with if you use this site. He could pass this site and your user name to people who have no business reading it while knowing who you are. You would be giving up your anonymity. He will spend weeks reading and rereading every last word you ever wrote here.

You may never net more than 17000 based on the fact it was such a short marriage. You had at least two periods living apart, so probably lived together as a married couple for less than three years. Even if the courts gave you more, legal fees could still leave you with less than 17000.

At this point, a truce may be worth contemplating.