I am of the view that having a relationship without a relationship property agreement in place is similar to living without a Will. Your intentions are left open to interpretation and can lead to acrimony upon separation. To avoid this, you and your partner can agree about the status, ownership and division of relationship property before you start living together, during your relationship or after separation.
During a relationship both partner's assets, liabilities and income may become intermingled. One partner may need protection from the other, this is especially true if one partner has more assets and/ or liabilities than other. It is not uncommon for one partner to contribute more towards the deposit for purchase of a property. Even when young couples start out afresh, it is common for parents to help with a deposit, such contributions need to be protected in the event of separation.
If there is a relationship property agreement in place, upon separation it circumvents the expensive, long and stressful process of applying to court for orders to divide relationship property.