“a better view may be that matrimonial property is not something that is predetermined at the outset of a marriage, but is governed by the parties’ intentions and how they treat the relevant asset over a period of time. Thus where a party has demonstrated an intention to use an inheritance for the benefit of the family, by translating it into actual use and enjoyment, the parties have elected to treat it as matrimonial property, even if its origin was from outside the marriage.”…it is our view that it is the parties’ treatment of what was initially non-matrimonial property, over time, as shared between them, that is central in deciding the fairness of that property being viewed as matrimonialised.”