@ojacobs08
Everyone who has replied already has given great counsel.
Here's a summary that I agree may help:
-read books and educate yourself
-take classes, through Alzheimers Association or free videos online like Teepa Snow
-look into local support groups through your medical facility or call Alzheimers Association's 24/7 hotline to find one near you (and Mayo hosts a weekly virtual support meeting for Caregivers on Thursdays, look under Events link on Caregiver main page on this Mayo blog)
-even though your husband isn't a Senior yet, you may want to check in with your local Senior and Disabilities group, or social worker
-Karla mentioned qualifying for certain treatments, and you may want to join a research study at a local university
-I personally think you should tell your children and parents. Yes, it will make them sad and upset and may increase their burden, but you NEED their support and they need to know what is happening to their loved one (they may be more upset later when they find out you didn't tell them earlier).
My husband also didn't want me to tell anyone, but I told him no, I needed the support and loved ones and friends (true friends) will be there for you.
-making sure you designate Power of Attorney and make tough decisions now regarding Advanced Directive, your Wills, and decisions regarding what type of care and ultimately a facility that he'd want to be in (if it comes to that).

This is a lot, so pace yourself, begin taking anecdotal notes regarding his 'off' behaviors that will help medical personnel, keep exercising and taking care of yourself since you'll need to be physically and mentally strong (and see a therapist experienced with working with caregivers to help you process all this).
Remember to take a minute for your interests and passions when you can, because you will begin to lose yourself as more and more demands are made of your time.
All the best to you, and keep checking in here; we got your back.
☺️🌻