Gosh congratulations to you lot too!
loukr - my mum was forced to make the same decision, i know she didn't want to either as she's been with my dad for about 25 years. But she had no choice and it was mainly for me and my brother that she made him leave. My dads an alcoholic, a drug addict, can be very verbally abusive and has had an affair (think he probably still is)- where as my mum is the softest, kindest person in the world - so she feels like she has to stand by him and support him, despite everything's his done to her and still does to her.
She still lets him stay at ours and stays at his place A LOT. So although she made a big decision in telling him he has to move out, unfortunately i dont think she's strong enough to move on...