When you have spent your almost entire adult life being in a relationship and bringing up children, then become an empty nester and lose your lifetime partner fairly close together, what you say and feel might not be what you do - but its really difficult to function outside those roles - whatever the role she took was for all those years, it is a role she has played for so long she doesnt know any other way to be, and yes in those circumstances anyone might feel they cant function outside of that role so need some-one to stand in as a companion. and whether thats the companionship of a woamn or a man isnt really relevant but if you are just not used to female company then making that change isnt easy - but she may discover that women friends can be funny and witty and adventurous and loyal and she may enjoy that discovery. Out of my closest friends three are men - one i have known since i was seven because men can be all those things too.
If she meets a guy, you could be right and he wont come up to her standards but that is for them to resolve should it happen.
If the desire to meet some-one as a companion gets her to socialise outside her realtionship with you, she may come to realise through doing it that friendship and companionship is important and learn to take a different role and attitude to what has gone before in order to keep it with people who have no obligations too her.
She may find a bereavement group helpful in other ways and that going to one gives her the confidence to do other things and go to different places -which is a good starting point - buts its important to remember they are not dating sites - men there may not be ready to move into another relationship even one which is just companionship, and at the other extreme also to be cautious herself about what information she gives people initially or going places with some-one outside of going as a group -very occasionally a predator may slip through the net - so i would certainly recommend she doesnt go with the view to dating, but to taking those first steps, talking to other people sharing some of the things she is going through and finding friendship with either men or women over a period of time in which trust can be built.
If she has to be in charge in the kitchen then maybe go out for meals - every so often and take it in turns to chose where ( it sounds like your choice will be the less good one to her - but at least she wont be able to complain about the times its been her choice, or that cooking the meal is bothersome.) - the together time could then be spent in the planning - do we go to town,do we go a bit further, what else is in the next town she might like to see - how will we get there, what date suits us both,what are the reviews on trip advisor like - etc etc. THis wont feed her proerly of course but you could send her ideas or if you make a big shepherds pie take some round for her that kind of thing. Is there something she was good at - scones biscuits or something that you could extol the virtues of and get her to want to make for you to take home.?
basically let her know that you are not abandoning her, you will spend time with her and help her out with some things - maybe the garden if she has one - or putting the rubish out - things she struggles physically with perhaps - but at the same time being firm that you dont want to move back in.