One can wear black even to the Buckingham Palace. It is both formal and informal. Most widows of my generation wear white and look radiant. They do not long for masculine company. They would rather spend their evenings at a shrine, praying or listening to bhajans .
Society approves of such pastimes for widows.
Personally, I would like all widows to get together, crack jokes about the leacherous people they meet and laugh their heads off. I would like them to seem happy. Temples and churches do not seem to be happy places. If happiness is proved by merely a smile, one can wear a laughing mask in company. One must begin the habit of wearing masks to reveal the true feelings or to conceal them, whichever seems best.