The financial aspect of a relationship will need to be considered at the time the relationship ends.
In order to ensure that any financial settlement is appropriate and fair, you will both need to disclose full documented information about your finances. If it later comes to light that one of you has held back information about assets, any agreement reached may be disallowed.
Once a financial settlement has been agreed, it is generally sensible to have the terms of the agreement set out in a document known as a Consent Order, which is drawn up and endorsed and sealed by the court. No other form of agreement will amount to such a guaranteed and binding solution.