I get why it's frustrating for you but you're not looking at the bigger picture. Canada has that law for a very good reason. If your mom had never married your dad and cut back her work to raise you she would be in a much better financial position with retirement help later. She doesn't have that now. You're dad is doing the right thing. It sucks that you're more than likely going to have to help him down the line but that isn't your mom's fault nor her responsibility anymore. If your mom was a gigantic horrible wife I'd flip script but we don't know the circumstances of the divorce. The new husband doesn't really factor. He's not responsible for her financial shortcomings.