Does keeping away from my mother-in-law—who causes me to sin with her lies and backbiting—count as severing ties of kinship?

The sacred texts prohibit abandonment and discord among Muslims, especially among kin, as it is a graver sin. Therefore, it is obligatory to mend ties, in compliance with the words of Allah Almighty: "So amend that [relationship] between you" (Quran 8:1) and the words of the Prophet, peace be upon him: "Mending ties." Your aunt is a relative with whom ties must be maintained and severing them is forbidden. It is not permissible to abandon her even if she wrongs you; rather, be patient with her harm and treat her kindly. The one who maintains ties is not he who reciprocates good deeds, but rather he who connects with those who cut him off and acts kindly towards those who wrong him. And whoever does that will have Allah's help and pleasure. As for your aunt's sins and instigation, you must advise and admonish her. If she persists and you fear that your relationship with her will lead you to sins, then be moderate in the relationship and limit it to the extent of maintaining ties only. And a warning: informing your uncles and aunts about what this aunt says about them is forbidden and constitutes backbiting.