Will I be getting part of my ex’s pension if we divorced 30 years ago?

My ex-spouse was employed during our marriage of more than 10 years. We had 3 children while we were married. We divorced 30 years ago. I am ready to retire and an advocate for insurance raised a question of if I received part of his pension. It was never brought up during our divorce and I never signed off of anything. We were too young to think of such things but I am wondering if I should be getting part of it. I retired after 30 years there and will be 66 in June.