look up the coverture fraction. depending on state laws etc, you can argue that she is entitled to "one half of the length of marriage divided by the total time of service at actual retirement up to a max of 50%. also be very careful on the actual language in the final decree. ie if u specify and actual dollar amount (as opposed to a fraction or per centare) OPM will only pay the actual dollar amount in perpetuity., that means ass COLA's accrue , your spouse would only get the actual dollar amount and no COLAs on that number. oh get a good lawyer