You should consult with a family, matrimonial, or divorce law attorney. As a general matter, once there is a divorce agreement or settlement, that settles the matter--an ex-spouse can't come back and ask for more than what was in the agreement. There are a number of situations, though, that may let her do this, which is why you should consult with an attorney; e.g.--1) You have breached your obligations (e.g. not paid what you should have), which may allow her to go back to court to look for payment from some other source;2) You lied about the existence, terms, amount of, etc. the pension, so that the agreement was not entered into knowingly;3) Without fault on the part of the ex-spouse, it was impossible for her to know of the existence or amount, etc. of the pension.Therefore, while generally, an ex-spouse can't open up a divorce ageement to seek more, you need an attorney to evaluate the specific facts of your case.Good luck.