Anyone done this?

http://www.ssa.gov/retire2/divspouse.htm

Just something i seen and started looking into it.

Im older than ex, so id hit "retirement" age first, was married over 10yrs, she got remarried, I did not. She is self employed and part time Military, but when she was working, she made more than me. From what I understand (and correct me if im wrong). SS takes into account the 3 highest pay years you had, not just the last years of working. Is that correct?

You have several misconceptions about Social Security.

Benefit is based off of the average of 35 years.  With no benefit incurred if you don't hit the 40 quarters of credits.

If she was military the she was paying in to a government pension plan.  People that pay in to a government pension plan don't pay Social Security tax and that means that that income doesn't get counted towards income in the social Security calculation.  Depending on credits earned she may not receive any Social Security, especially after the Windfall Elimination and Government Pension Offset are invoked.

http://www.ssa.gov/pubs/EN-05-10070.pdf

It may be different for active duty, but for civiliians they switched pension plans a few decades ago and some pay into SS and some don't.

The civilian side depends if you're on FERS or CSRS. CSRS was the old pension plan and they didn't have to pay into SS. The newer plan (implemented in the 90's??) is FERS and they DO pay into SS just the same as everybody else... I'm not sure if the armed-forces side followed suit or not...

Military personnel pay SS taxes.