Aw
@PJ that's bad news, but there is a good element. Bad about the dementia, but good about the care and understanding you will now get because there is a diagnosed reason for the symptoms you experience.
You and your husband will now likely experience a period that feels like grief(anticipatory grief); we did but in my case it has passed and in my wife's case it has eased. Depression and anxiety may kick in and initially my wife was put on Duloxetine and Pregabilin when she was at the MCI stage - which helped her function but didn't help with the symptoms of the dementia. My wife's dementia was eventually diagnosed as being caused by Alzheimer's(the most common cause) and she was put on Donepezil and Memantine which have helped with the dementia symptoms. My wife takes the Alzheimer's meds at night and she has tolerated them well. If she takes those meds in the morning they make her feel very sick(a common side effect).
This is the time when you should read all my posts again to remind yourself of what I have said about being able to live well with dementia because every word I have written is the truth. If you have any questions at all just ask away. Try your best to stay positive as it's not the end of the world.
If it has not already been suggested, now is the time to make sure things like POA, Wills etc., are sorted out. Apart from that, another thing I did was move forward plans for renovating our apartment so that things like the bathroom and kitchen would better suit future needs and my wife would have time to enjoy and get used to the new layouts before they would cause confusion.