Its only a cultural thing that we raise an eyebrow at a woman being/looking older than her husband.
Older women can easily attract younger men and not just in a motherly way but in a sexual way. Women in their late 30’s and early 40’s who are reasonably maintained can easily attract men in their 20’s.
There is a misconception that age affects men’s desirability less than womens. The reality is that older women can attract men much more easily than older men can attract women. In most cases older men need to leverage their status or money to attract younger women. Older women can attract younger men w/o using their status.