Think about using assistive technology -- devices that can help keep you mobile and active. You may have to equip your car with special tools so you can still drive. You may need to put grab bars in your bathroom to make it easier to shower and use the toilet.
Someday, you may even need to remodel your home, or move, to avoid stairs or tight spaces that make using a wheelchair difficult.
Ultimately, these changes are about keeping your quality of life. This doesn't mean you're "giving in" to your PPMS. It means you're taking charge.