I recommend you get advice from an elder care specialist firm (they usually combine tax planning, financial planning and legal planning). There are things you need to know now, and plans you can make. At some point, if your spouse becomes disabled enough to require nursing home care (more advanced than assisted living), Medicaid may pick up the cost, but that can have strings attached.
While your spouse needs assistance, but not full nursing home yet, some states have a Medicaid program that will pay a caregiver (including a spouse) to care for the patient in their home, because it is less expensive than going to a nursing home. These difficulty-of-care payments are usually not taxable to the caregiver. However, these programs are complicated and vary from state to state, and you should at least speak to a social worker to assist you in navigating the options, if not a full elder law and financial firm.
https://www.irs.gov/individuals/certain-medicaid-waiver-payments-may-be-excludable-from-income
https://www.aarp.org/caregiving/financial-legal/info-2017/you-can-get-paid-as-a-family-caregiver.htm...
https://www.payingforseniorcare.com/paying-spousal-caregivers
https://www.medicaidplanningassistance.org/getting-paid-as-caregiver/
