There are plenty of alternative ways of dealing with this issue but they all involve some sort of cost.
This only affects a very small number of people. If there are no children (or the house is not left to the children) then this will affect people living in houses worth more than £650k (excluding any mortgage) - assuming there are not other large assets.
If the house is left to children then this affects people with a home worth more than £1 million.
For context, the average price of a home in England in Nov 2024 was £306k
Flats & maisonettes - £252k
Terraced houses - £256k
Semi-detached houses - £298k
Detached houses - £459k
.
OK, let's assume that you and your DP have no children and live in a £1 million house with minimal other assets (to keep things simple).
Suppose that your DP passes away and leaves an estate worth £500k (half of the £1 million house). In this situation there will be IHT to pay on £175k (500k - 325k) at 40% or £70k.
So you will need to have that £70k to pay the IHT. I would strongly suggest that you speak to somebody experienced in this area about how you can achieve this by planning ahead.
There is a body called the Society of Trust and Estate Practitioners (STEP). Solicitors that have qualified to become members of this society really do have a great deal of knowledge and experience in this area. If you google something like "STEP solicitor [name of your town]" you will get a list of local solicitors.