How do we spilt the profit from our house?

Firstly, the debts that your girlfriend has built up on her credit card are hers and you cannot be held liable for them.

As she has been contributing to the mortgage, she will have a beneficial interest (financial interest) in the property. The size of her beneficial interest will be in proportion to the amount she has paid. So, for example, if your initial contribution was 20% and hers was 0%, you immediately have a share of that 20%.

When it comes to ongoing mortgage payments, if you were paying 80% and she 20%, you would have a bigger interest than her. If you decide to sell the property, the sum remaining once the mortgage is paid is divided between you based on the percentage each of you paid.

It’s better to try and sort out this division of profit amicably, as getting lawyers and courts involved can be very costly.