The most important thing you can do right now is to have your husband evaluated by your doctor. He/she may decide to refer you to someone who specializes in problems that older people often face -- but either way, you need to know what's going on. From what you say, your husband may be facing Alzheimer's disease or some other type of dementia.
In addition, your family needs to be aware of what's happening to him (and to you). Your letter doesn't say if you have children or other close relatives but if so, they need to be informed. You need them right now -- and you may need them even more in the future to help carry your burden. The Bible says, "Carry each other's burdens, and in this way you will fulfill the law of Christ" (Galatians 6:2).
Don't be embarrassed by what's happening or think that it's somehow shameful -- because it isn't. I recall visiting former President Reagan several times as Alzheimer's began to take its toll on his memory and personality. I'll always be grateful for the way he and his wife, Nancy, spoke openly about it when it was first diagnosed.
The days ahead may be hard for you -- but God has not abandoned you, and ahead of you is the hope of heaven if you know Christ. No matter what happens to us God's promise can be trusted: "Never will I leave you; never will I forsake you" (Hebrews 13:5).