I agree with MOnica.
My husband is a gregarious, outgoing, sociable sort but has always struggled in the winter. Lockdown hit him hard and as I was working, he did start to go a bit 'dulally' as he put it. Drinking a bit more, getting moody and difficult.
I have retired now too so he has me as company more. It is important to have your own space and back off when he is having a tantrum.
I can't speak for all men's problems, but I do think falling testosterone levels can affect self esteem, and if they have always been fit, then even small health changes can hit them in the ego.
Men aren't ones to talk about their feelings generally, and not like us girls who are quite happy to talk about ours with a friend. I do think they need other male contact though.
At the end of the day, it's his life and he's a grown up. You have your own life, so seperate yourself emotionally if not physically and maybe he will get the message