More than a fifth of women said they have “secret savings” they keep in case they split from their partner, according to a 2,000-person survey from Fidelity International.

Twenty-two percent of all women said they had such a savings pot, rising to 27 percent among women with children.

About half of the women with a secret fund said they wanted to be prepared for any eventuality, with most others saying they wanted to maintain a sense...