There is no single area of law which assists on the breakdown of a cohabiting relationship. Although the government was going to implement changes in the law some years ago, nothing has materialised. The areas which are there to assist, (albeit not unified) relate to property rights and claims on behalf of children.
We can assist by formalising your arrangements with a Cohabitation Agreement which will define what might happen to your assets and the relationship with your children if your relationship breaks down.
An interesting article about this topic from Deborah Levy: Cohabitation and the law: an overview