It is different in every state. If your state is Michigan, there should be a standard formula used based on how long you were married, what your education levels are, how long you worked, your salaries, etc. that spits out a standard dollar amount for X number of months. The fact that you were married 31 years would work to your advantage, but might be offset if you have a graduate degree, earn a lot, etc. Any L should run the formula and give you the same numbers. Now the judge may decide to pay more or less than the formula if there are special considerations. A L should be able to tell you if any of your circumstances would apply.
I know Michigan is a fault state, but I forget how much that matters. It may just be you can make him pay for your L fees, etc.
IMHO if your income is that different from his and if there are any significant assets (or debts) at stake, it is critical you have a L represent you to protect your interests. Your WH can always represent himself to save money, if he wants. 
