If you have any joint finances with the ex, or had, you will be associated on your credit files. You will need to contact each agency and disassociate yourselves. So, if associated an IVA on one can reduce the credit score of the other.
Is the home address owned by the both of you -- if so, the equity will need to be released towards the end of the IVA, or the IVA extended, if release isn't possible.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014 http://foggy.blogs.iva.co.uk