In the short term you should be able to protect your occupation rights by registering a claim at the Land Registry.
http://www.landreg.gov.uk/ This would mean you get to stay in the home even if your husband sells it to a third party (at least until the courts decide what's going to happen to the house).
I was always under the impression that because you've been cohabiting you're pretty much entitled to half the house anyway, whether your name's on the mortgage or not. Obviously, I ain't no expert tho! I'd have a quick word with the CAB first
http://www.citizensadvice.co.uk/