DISCLAIMER: Advice provided based on limited information poster provided. In another post she said she was not yet a certified board-licensed dentist.
First of all, the longer you and your spouse can't compromise on an arrangement the more money the lawyers make... in fact, they are counting on the two of you fighting it out so they can increase billable hours on both sides. Hopefully you and your ex, to date, have received timely accurate bills from your respective lawyers so you both know the costs involved in lengthy litigation. If you haven't you should do that immediately.
SS is not cut-and-dried like child support. Many factors are considered. Length of marriage and age of people is important. Of course his lawyer has blown smoke up his arse and your ex likely truly believes that SS is based merely on difference in income and future earnings. Even 20 years ago when someone put the other person through university to earn an MD or specialist, it was an uphill battle for the claimant.
Rockscan is correct in that one party has to prove entitlement. Hopefully, you haven't conceded this yet and doled out interim SS. If you have then you have pretty much conceded his entitlement. I can't imagine competent legal counsel caving on that surely?
While your STBX is gathering information you might want to empower yourself with information gathering of your own. Some things that come to mind would be your man's resume, income tax returns... anything financial. You want to get the most information on your ex's untold, unlimited skills and abilities.... Of course all detailed finances that you can transpose to spread sheets (keeps the judge's reading easy) with corroborating information, is something your competent legal counsel has already instructed you to amass? If you have all the documentation to support your assertions then you should be feeling confident.
The other part of the plan that competent legal counsel would be advising you of is the unlikely situation where you have to pay a nominal amount of SS. If your ex is currently unemployed do you have rigid requirements in your agreement outlining employment searches? Do you have a specific review date in the agreement? Have you contemplated a step-down approach of weaning your ex from the SS should you have to pay (gradually increasing imputed income)? Finally, have you been counselled about binding arbitration as opposed to trial? You are a professional and you certainly don't need your good name, and divorce details, available for anyone to read. Binding arbitration is private.
Good luck.
