Married for 17 years, divorced for 4. I am 50, he is 59. He makes 4x what I do - is there a way I can find out how much I will be getting without knowing what his SS benefit amounts are? Is there a way I can find that out? Am i correct that I have to choose using either his SS or mine?

Ruth,
Yes, you can ask Social Security what your divorced spouse's benefit would be at your full retirement age. Be sure to ask only about your benefit; don't ask about his earnings or his benefit, they can't tell you that. And yes, you can collect either your divorced spouse's benefit off of his record or your retirement benefit off of your own record, whichever is larger.
Best,
Mike