What is the ruling on a widow masturbating for fear of falling into the unlawful, especially if it is at infrequent intervals and sometimes requires some stimulants, and she cannot remarry?

Masturbation is forbidden in Islamic law. However, if a person fears falling into adultery and is faced with one of two paths: either adultery or masturbation, the latter is lesser in sin, because committing the lesser of two harms is a legitimate legal principle. As for exposing oneself to provocations, it is forbidden and must be avoided.