All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
Allaah Almighty has enjoined his slaves to maintain ties of kinship and forbade severing them. Allaah Almighty says (what means):
• {And those who join that which Allaah has ordered to be joined and fear their Lord and are afraid of the evil of [their] account.} [Quran 13: 21]
• {So would you perhaps, if you turned away, cause corruption on earth and sever your [ties of] relationship?} [Quran 47: 22]
The kinship ties that should be maintained and are prohibited from being severed are those related to fathers, grandfathers—no matter how far the line of ascent reaches—and the children and grandchildren—no matter how far the line of descent reaches—brothers, sisters, paternal uncles and aunts, and maternal uncles and aunts, and all of those who are of their status from among the Mahram (unmarriageable kin) persons. Maintaining ties with relatives other than those is just recommended and not obligatory according to the most preponderant opinion of the Muslim scholars. Accordingly, the wife of your maternal uncle is not included in your kinship circle of those whom you have to maintain ties with, as long as she has no other relationship which puts you under the obligation of maintaining ties with her. Rather, it is just recommended to maintain ties with her. As for slandering a Muslim individual and accusing him of committing immoralities, it is one of the major and grave sins that doom a person to Hell. The Prophet, sallallaahu ‘alayhi wa sallam, combined it with Shirk (polytheism), sorcery, killing a soul, consuming Riba (interest), devouring orphans' wealth, and fleeing from the battlefield. This was reported in a Hadeeth that was narrated by Al-Bukhari and Muslim. All this indicates that the matter is very serious, so—following the condition stipulated by Allaah Almighty—it is not permissible for a Muslim individual to utter something to that effect as long as there is no clear evidence that is not open to interpretation. We advise you, O respectful questioning sister, to stop talking about that evil matter because doing that entails evident harmful effects upon you and upon the society as well. If you do not feel comfortable with the wife of your maternal uncle due to her lack of bashfulness or any other reason, then you can keep away from her. We ask Allaah to grant us all guidance and successfulness.
Allaah Knows best.