A: What's really going on here? One argument can't transform your stepmother from adored to detested. My hope is that your father and his wife can try to reconcile their differences. Notice I didn't mention you and your siblings—this isn't your problem to manage.
If your dad and his wife can no longer live compatibly, then he should move forward with divorce proceedings. Staying put because he doesn't want to give his spouse her share of the assets accrued during the marriage is unacceptable. People first, then money, then things—money never comes first. If he made more, he has to split more—that's basic law and basic decency. In community property states (Arizona, California, Idaho, Louisiana, Nevada, New Mexico, Texas, Washington, Wisconsin), spouses divide both debts and assets equally. In any other state, your dad, his wife, and their attorneys will have to work to reach an equitable agreement.
I'd love it if more couples could divorce with dignity. Sound crazy? It's anything but: A growing number of people are using what's called collaborative divorce. This new paradigm puts a premium on couples working together with mediators in a respectful manner to formalize the split. Because it circumvents the need for a court trial, it can be a less expensive route too. You can learn more about collaborative law at CollaborativePractice.com.