What is the ruling on a woman returning to her divorced husband who is an innovator (mubtadi') when there is a child between them?

If the husband holds a disbelief-inducing innovation (bid'ah mukaffirah), his wife is not permitted to return to him. Among the disbelief-inducing innovations are: claiming that the Companions apostatized after the death of the Messenger of Allah, peace and blessings be upon him, except for a few; or claiming that the Holy Quran has been distorted; or believing that the Imams and saints can cause benefit or harm; and also slandering Abu Bakr and Aisha, may Allah be pleased with them both.

However, if his innovation is not disbelief-inducing, such as celebrating the Prophet's birthday (Mawlid) or the day of Ashura, she is permitted to return to him, while taking into consideration what is best.