If corrupt bishops move to supposedly nullify holy marital vows, it's a mortal sin on the part of the bishops and it is contrary to Canon law as well as contrary to Divine and Natural Law. Just as it would be a violation if, under the present arrangement of Canon Law, corrupt marriage tribunals presumed to "dissolve" validly-contracted marriages.
The law still stands ---- and will always stand --- which recognizes that a valid marriage requires exclusive sexual fidelity until death. I.e. no "second "marriage".
The same applies to corrupt popes who give free reign to those corrupt bishops.