What should a married woman do who has been mistreated by her husband, then committed adultery, and now wishes to atone for her sin and secretly marry another man? Is marriage without a guardian (wali) valid? And if not, is it permissible for her brother to be her guardian instead of her father to maintain secrecy?

The questioner must make sincere repentance for the crime of adultery, and the husband must also repent. If a divorce occurs, the questioner should not marry the fornicator unless he repents.

It is permissible not to publicize the marriage if there is a benefit in doing so, provided that the Sharia conditions are met, including the presence of a guardian (wali). It is not permissible for a more distant guardian (e.g., a brother) to act as a guardian when a closer guardian (the father) is present, unless the father refuses to marry her to a suitable partner without a valid reason; in that case, the more distant guardian may marry her off.