The sacrosanct nature attributed to families needs to be questioned. We need to start expecting good behaviour from family members, all family members regardless of age and gender, and be responsible for good behaviour towards them from our end. If a particular family member is hampering one's emotional wellbeing, that needs to be openly tackled by discussion. And if the other party doesn't own up to how their behaviour could be influencing us or isn't ready to work on the relationship, then clearly our relationship isn't a priority for them. In such a case, moving away should definitely be a legitimate option.
One needs to understand that sometimes taking a child out of a toxic family arrangement, to be raised by a single parent could actually be the most child-friendly decision possible in that context. There's no dearth of research showing the debilitating impact of domestic violence and marital discord on children, and many of these effects last well upto adulthood. Very often, these children become adults that have a tendency to either become abusers themselves or to accept abuse because that's what was modelled as normal behaviour in a marriage/family for them. Grandparents, uncles and aunts, and lots of cousins living with us, sharing in our joys and troubles, having both of our parents living with us, may well make for a wonderful life- stuff of dreams for many of us- but only as long as staying together doesn't become more important than the wellbeing of the individual members. Family can be the best thing ever- our own army against the rest of the world and the one place where we can always take refuge; family can also be the one thing that has the most potential to bring us down- an invisible soul sucking enemy. So, if some day the institution of family becomes more important than the sanity of any of the individual members, a long hard look becomes imperative at what one is getting out of the family and at what cost.