Ex husband entitled to half equity

Hello

Just a quick question...

My ex husband is currently paying around 15% towards mortgage, which is in negative equity by a substantial amount.

If ex was to stop paying and I continued with payments until such time as in equity (around 7 years worth) would I automatically have to share equity with him or is there a part of divorce that will take away any right to equity or do I just have to bite the bullet if I want to keep the house? :eek:

Any comments appreciated.