Mrs. White is a strong woman, and the narrator even says she's smarter than her husband. We get the sense that she makes lots of decisions for the family and that her husband is happy with this reversal of traditional gender roles.
As mentioned in Mr. White's section, she might go a bit too far sometimes, to the point of forcing Mr. White to do things he thinks are wrong, like wishing Herbert back to life. Some readers see her as mean and dominating.
In our discussion of "Genre" we argue that "the Monkey's Paw" is probably inspired by a story in One Thousand and One Nights. (Mrs. White actually mentions Nights, though she calls it Arabian Nights, as it is sometimes known.) The original story is meant to show that women give bad advice and can't be trusted. (Ugh.) Who knows, maybe W.W. Jacobs, author of "The Monkey's Paw," is playing around with this idea?
However, the narrator has already told us that Mrs. White is smarter than her husband. If this is the case, then her advice is probably usually helpful to Mr. White, right? In fact, we only know of one bad piece of advice she offers, the advice to wish Herbert back to life. Her decision is obviously guided by extreme grief. We really don't know enough about her to judge her decision-making ability.
What we do know about her is that she is extremely loving. She loves her husband and son and is willing to do anything to hold the family unit together. As with Mr. White, Mrs. White's story is tragic. She goes from being basically happy and cheerful to almost losing her mind to grief.