Hold on ....... what about these credit cards ? She obtained these fraudulently - without your husband's knowledge, so why on earth should he have been liable for those debts ?
Did DH report this to the police ? She has committed a serious crime and as such, should be bought to task. I can't believe that legally, nothing could - or still can - be done about this.
What about the credit card companies themelves ? Surely they would have had to supply a list of transactions, dates etc., and, if in dispute, I should have thought they would have also had to provide copies of "DH's" signature - which obviously wouldn't have been his.
Furthermore, I have never heard of credit cards being secured against property. Loans - yes, credit cards no. But nonetheless, even if she did somehow secure any sort of debt on the property, it would have been done fraudulently, so we go back to the fact DH should not be liable.
It shouldn't have been a case of YOU having to get her to accept any of the responsibility ..... this should have been the Police's and/or Credit Card companies job !!
Have you /did you seek any legal advice about this ? It absolutely ISN'T right - and, I should have thought, be relatively easy to prove DH is entirely innocent.
Putting that aside for a moment, I'm sure you agree that DH should be paying CSA miniumum child maintenance for his son ...... but certainly nothing for her. Though I do appreciate the credit card nightmare must wrankle and it'd be easy to compare the expense of that against the money she's now demanding.
The £20k of equity is probably something you will have to "swallow" ...... it does seem ridiculously unfair given she never put anything into the property AND got 2 years worth of accommodation rent-free and with bills ..... but I suspect the court awarded this sum "in the interests of the child" (no doubt she argued she needed it for that purpose) and to help house him.
I really do think the best thing you can do is sort out the credit card mess as that is the out and out grossly unfair thing in this situation, and the injustice of it all must be doing your head in. Quite how it would work now that you've actually paid those debts off I don't know ..... I suppose she would become liable to pay DH, and perhaps he could argue that whatever he's legally obliged to pay in child maintenance is offset by what she owes him until that £12k debt is paid off, at which point he then starts paying at least minimum CSA again.
However the finances are worked out though, it doesn't alter the fact she is guilty of a number of crimes - identity theft for one, fraud for another.
I fully appreciate how sickening all this must be .... I'm not going to spend ages writing about my own situation but my DP too was dragged through the mire financially by his ex, severely limiting our purcahsing potential (the effects of which we live with on a daily basis while she sits pretty). What's worse is that she deliberately obstructed sorting out the finances for 2 years, racking up huge legal fees - even though they had already made a more than fair settlement when they originally separated. But the greedy b couldn't resist coming back for a second bite of the cherry.
I hate to put the frighteners on you but I used to think that one day we would be allowed to have our own life but more than 5 years after meeting DP, and 7+ years after they split, her gross spite is worse than ever. Yet again she's been at it today with snidey texts accusing DP of all sorts. I'm sort of resigned now to the fact it will never change but I hate it and her with a vengeance.
So no ..... you're not unreasonable, but please please do something about those credit cards. You read about people's cards being scammed on holiday - being charged £300 for a £30 meal, that sort of thing - and the company is usually understanding. How on earth her debt has become your DH's responsibility I don't know ?