Skipping the fact that your husband was an abusive person and may still be an abusive person, here's a thought. Instead of making it HIS WAY versus HER WAY, why not offer something different? For example, his way is "open the books and have a FRANK discussion (which sounds like a fight to me) then make an offer we'll find offensively low and yell". Her way is "hide the books and all records and rugsweep the fact that you two ever participated so that none of your effort is acknowledged or compensated."
Why not make an educated guess?
I mean, as you worked the business one of the two of you (you or your hubby) must have some idea of the clients or sales from the business, the capital used to keep the business afloat at the beginning, some of the expenses of the business, if there were loans taken out, if people got paychecks, etc. Thus, if you use your best guess, and you two were with the company three years, and you GUESS that it made nothing the first year, $10k the second year, and $50k the third year...and you two got paychecks all three years...and you invested $50k capital to start... you say "Okay our capital back plus our guess of $60k profit over 3 years divided by 3 of us = $20k profit per person to buy us out and we're done."
In other words, give it your best, honest guess and have some reason to back up your number. Make an offer of your capital plus whatever number you came up with to buy you out. Say "Here's what we are proposing as a start--make a counter-proposal."