Over the years, my wife and I have known a number of people who've faced what you are now facing, or who were themselves victims of this terrible disease. My heart goes out to you.
I want to assure you also that God knows what you are going through and He cares for both you and your husband. The Bible says that "those who hope in the Lord will renew their strength" (Isaiah 40:31). May this be true for you as you look daily to Christ for wisdom and help.
The time will probably come (if it hasn't already) when you will no longer be able to give your husband the care he needs. Ask God to help you to know when that time arrives, painful as it may be. The key is to decide what will be best for him (and yourself). You love him and therefore you want him to have the best care possible–even if it is in a nursing home. He would want the same for you if your roles were reversed. Jesus said, "Do to others as you would have them do to you" (Luke 6:31).
God never gives us burdens that are greater than we can bear with His help. You may even find that your time with your husband will be richer once he is in a health care facility because you won't be burdened with many of the things that worry and exhaust you now.