Quiet divorce is when a couple check out of a relationship without actually separating.
They might still share a home, finances, social obligations, even holidays, but emotionally, they have retreated from the usual intimacies of a long-term relationship to lead parallel lives.
Perceived upsides include tax efficiency and financial stability, a preference for peace over constant negotiation, avoiding emotional upheaval and preserving stability for children.
The possible downsides include difficulty meeting someone new, assets up to the date of separation form the marital pot (whereas those generated after separation are not) and confusion and uncertainty for children who are aware of changed dynamics.