Abraham, Isaac and Jacob were adulterers?
It's highly unlikely that these people are Christians.
L
It appears to me you are mistaken.
1 Timothy 3:2
A bishop then must be blameless, the husband of one wife, vigilant, sober, of good behavior, given to hospitality, apt to teach;
So that is a specific qualifier for persons in the Role of Bishop.
It is not even a prohibition for those above the position of Bishop. Certainly not a prohibition of polygamy for the body.
Bishops perform a special role in the church (generic) and have some special job pre-qualification standards.
Could you reference within the new testament what it is you base your contention that polygamy is prohibited and adulterous?
W