I think you are both going through so much at the moment.
You with the loss of your Mother and coping with the menopause.
Then on the other hand your husband is having to cope with retirement.
It must be difficult for him to suddenly have a high powered job one minute where he is in control to be at home where he probably feels lost.
A lot of men find retirement hard to come to terms with.
Does he have outside interests?
Befor you make any sudden decisions i would get him to sit down with you and try to talk about what is happening to you both, and what if anything you can do to to ease the situation.
Tell him that you are so unhappy at the moment you are. thinking of giving up on your marriage.
He might not realise how desperate you are.
Men somtimes find it hard to express themseves, he could be feeling just as bad as you do.
I think communication is the key word here.
I do hope things work out for you.