A more thorough explanation:

Widower

A widower is a man whose wife has died and he has not remarried since then.

John's wife passed away last year, and he has been living alone since then. He is a widower.

After his wife's death, Tom decided not to remarry. He is now a widower.

These examples illustrate that a widower is a man whose wife has died and he has not remarried since then. It is a term used to describe a man who has lost his spouse and is living alone without a partner.