There are two issue here
1) does she have a fiancial interest in the house. To answer that one needs to know what was agreed about the ownership of the house when it was purchased, if the house is in joint names, and if so upon what basis, and what contributions she has made towards the acquisiton or improvement of the house. Paying domestic bills and buying furniture is rarely enough on its own to generate a beneficial interst.
2) What can a divorce court do. If they are already divorced, and if any final orders have already been made then the court orders are conclusive of the issues they deal with. If they are not divorced and divorce proceedings are commenced then she can always apply to the court within divorce proceedings for a transfer of property order, or a lump sum order, which will take into account her interst in the house or entitlement to claim one. If they are divorced but no orders have been made she can still apply unless she has remarried in which case she loses her right to make such an application.
As to what the court would think is fair depends on all the circumstances