Is it forbidden for a man to follow his wife's madhhab (school of thought) in the ruling that madhy (pre-seminal fluid) is pure, after he had been following a madhhab that considers it impure, and is it incumbent upon them to change that and wash everything that the madhy has touched?

The impurity of madhy (pre-seminal fluid) is agreed upon by scholars, and the text (religious evidence) establishes its impurity. There is no recognized school of thought that considers it pure. Both men and women must purify themselves from madhy; they should perform istinja' (washing the private parts) from it, wash whatever it touches on the body, and sprinkle water on whatever it touches on clothing. It is not permissible to follow someone who issues a fatwa (religious edict) contrary to this. In matters of permissible scholarly disagreement, an ordinary person should follow the opinion of a scholar whom he trusts, and not follow another ordinary person like himself.