OK - calmly look at the finances - what is the income split? Do you want to stay in the house or sell up & cut your losses? How do you want to arrange things with DS? Are you able to speak to eachother reasonably? If so - try to keep it like that - don't involve lawyers unless absolutely necessary.
Ok - so is XP happy with that? Are things amicable at the moment? Would he be happy with you being DS main parent & the support that would need from him? Have you discussed any arrangements? Are you married?
ChildofIsis and Jareth Go to this website http://www.turn2us.org.uk/benefits_search.aspx It will tell you what you are entitled to in terms of benefits. I was amazed at how much of a difference the tax credits would pay - I only work part-time too - and felt soooooo much better about the whole thing. Enough money to pay the mortgage, all bills, childcare, eveything. Let us know how you get on.