Hi reesh and welcome to the forum
First of all, please try to understand that your wife has been pretty brave in going and seeking advice, and probably agonised for a long time as to how to tell you about her difficulties.
It is possible that not all of the money she has borrowed has purely been spent for personal use, and that some of it may have been used to supplement family expenditure. I am sure that once you come to terms with the situation, and can understand how this affects you, you will be proud of her for doing something about it - when to be honest a lot of people would probably just keep borrowing.
Turning to the property, in an IVA your wife will be required to get the property revalued during the final year of the IVA and then look to raise borrowing at 85% loan to value. So using the current value of your property at £70k, and taking borrowing of 85% this would create a new loan of £59,500 - which less your current mortgage of £32,000 provides a combined sum available of £27,500 - of which her share would be £13,750.
This would need to be paid over in addition to the contributions she would be able to make over the five year period. Assuming that she pays at least £250 per month into an IVA, she may be able to repay her debts in full - so perhaps a better option at this stage would be to remortgage now, while interest rates are low, and pay off the money in a lump sum. This would of course affect your share of the property, but if done via an IVA your wife's credit rating would be affected for six years, thus limiting her ability to access credit over that timescale.
Bear with it - this is raw for you at the moment, and must have come as a great shock, but you have a little one to think of, and at the end of the day your family are the most important thing that you both have.
I wish you, and her, the very best of luck with whatever solution you decide to follow, and either of you need support you will find it on this site.
Regards, Melanie Giles, Insolvency Practitioner