Hi
@Raest, I am sorry to hear that you and your husband are facing this problem. You have already been given some great advice above.
I understand your situation because my husband was diagnosed at 58 and was very mobile and able to walk many miles at a time for several years after that and occasionally would knock at doors of houses in our road for a chat. There was no way he was going to stay home.
I wonder if you have used the Alzheimer's Society search tool to see what services are available near you? You can filter the search to the type of service you need e.g. activities and social groups, day centres etc.
I found that a lot of trial and error was involved. The first day centre we tried was a total disaster because, although they had experience of dementia, it was solely with older, less mobile people. Frankly, they were clueless about what to do with a younger, very mobile, energetic man who didn't want to sit around very much. Having said that, the second day centre was perfect for him and he loved going.
You can find the search tool at
https://www.alzheimers.org.uk/find-support-near-you
I found I had to do a lot of my own research too. I was lucky enough to find a local leisure centre which ran events for people with dementia. They would set him on the running track where he could walk laps to his heart's desire without fear of getting lost, which helped enormously.
They also ran exercise classes for people with dementia and from time to time he enjoyed 'walking football' there.
It might be worth checking out what is available at your local leisure centre as they are obliged to provide services for and be accessible to people with a wide-range of disabilities.
Financially, my husband qualified for the Personal Independence Payment (PIP) which was used to pay for these activities. That might be something to look into if you haven't already done so.
As was mentioned in another reply, do request an assessment via social services to see what they can help with.