I was married for 8 years . I got a divorce five years ago my ex want part of my penion is she entitled to it/ do we have to be married for a certain amount of years

It generally does matter how long you were married but what really matters is what is written in your divorce agreement signed by the judge. I'm guessing you knew five years ago that you would be getting a pension so it should have been addressed at some point during the divorce.

Also depending on the stae you filed in she may be entitled to 1/2 the benefit of the contribution to your retirement. Mostly it depends on your papers from the courts and if the state you filed in recognises 50 / 50 property rights during a marriage. You really need to go back to your lawyer and ask him / her because if it wasn't resolved before then you might need to go to court to settle it.

i was married for 8 years . i got a divorce five years ago my ex want part of my penion is she entitled to it/ do we have to be married for a certain amount of years
Welcome to AMHD. You were divorced five years ago? What does the divorce or separation agreement say about your pension?