This is incorrect.
Unmarried partners need only to demonstrate that prior relationships have permanently broken down. Religion prevents some UPs from obtaining divorce, and there's a significant number of successful applicants who are still married and will always be married.
Additionally, the UK does not have a visa waiver programme.
That sounds promicing, many thanks for your help. I will have to consult an immigration solicitor if it gets that far.
To answer Suzanne's questions, Andrea was not a factor in the divorce, in fact I only met Andrea after being seperated from my wife for 10 months, however my wife has now found out about Andrea which is why she has gone off the deep end and is getting difficult. The frustraiting thing is I was about 3 weeks away from nisi at which point even if she didn't apply for absolute, I could of three months later - grrrrr.
All of this has happend this weekend and hopefully she will calm down and see the light, however she might not and I have to be prepared for that.
Many thanks for everybodies help, its good to know that I have options. If it comes down to it I'll file for divorce 3 mths before Andrea's student visa expires to show that I have started proceedings and hopefully that will work.