The question of whether it is legally or socially acceptable to marry your son's ex-wife while your son is still married to her depends on the laws and cultural norms of the specific country or region involved.
From a legal perspective, in most places, it is not permissible to marry someone who is already legally married to someone else, regardless of the relationship between the two individuals. In such cases, marrying someone who is already married is considered bigamy or polygamy, which is illegal in many jurisdictions.
From a social and ethical standpoint, such a situation can be highly complicated and may cause significant strain on family relationships. It is essential to consider the feelings and emotions of all parties involved, including the son, the ex-wife, and other family members, before making any decisions.
In many cultures, marrying your son's ex-wife while he is still married to her would be considered highly inappropriate and could lead to significant family conflicts. It is essential to respect the existing marriage and the feelings of everyone involved.
If you find yourself in a situation like this, it is crucial to seek legal advice and consider the emotional impact on all family members before making any decisions. Communication and understanding are key to handling delicate family matters like this.