Sorry guys, I'm an outsider lurking here. But, I just can't resist adding that I think Caligula is spot on regarding x-wife's £400/month. She stayed home for how many years? While he travelled to promote his career? And then he should get out and have no obligations? OMG what about the life she didn't persue because he vowed to share his with her... and then changed his mind.
I'm sorry, but I just don't think anyone has the right to walk out and then think they shouldn't be responsible for however many years of promises that they no longer wish to honor.
Okay okay, I don't know your friend. Perhaps she's a whitch and deserved it. But, in general, I do think that women get a raw deal when their husbands (whose carers they have supported) decide to trade up for a newer model.
Hope no one kills me for this post... just think men have it too easy.