WTF??? What kind of "mediator" files a divorce action after only meeting with ONE party, and with only one party's signature???
You need to call this "mediator" immediately. Mediation is where two parties agree amicably to all of the issues, with the intention of filing an uncontested divorce. Typically the two parties will agree to all of the non-controversial issues ahead of time, as much as possible, and then -- in the presence of the mediator -- he/she will help you work out the remaining tough, sensitive issues. This is typically done over two to three meetings, depending upon how much mutual agreement there is going in. Once everything is agreed upon, each party can then have their own atty look it over if they wish (which I always advise!), and THEN -- if both parties are in agreement -- YOU FILE.
Again, WTF????
It sounds to me like your wife has just played you.