Please please can someone give some advice, really stuck

Hi

I would really really appreciate if someone please give me some advice.

I am currently on Tier 2 and my partner of 5 years is on Tier 1. I am about to loose my job and need to change the visa category. My partner is separated from his wife for more than 6 years now and is fighting a divorce case back home. His ex came to UK few years back as a dependent for 6 months. So I am assuming they will still have a record of that.

Now can I still apply for unmarried dependent visa on grounds that we are in a genuine relationship and he has no contact with his wife and is getting divorce? Do you think UKBA will reject my application because he is still legally married to his ex? Do I have a chance at this?? Any honest opinion/ suggestion will be greatly appreciated!

Thanks you.