I am suprised that this was not addressed when you agreed to the modification relating to equity release, and your wife's agreement sought.
Gizmo's advice is absolutely correct, and this will affect your ability to raise the equity you have agreed to raise - but the modification says 100% of the equity - which means your share. Your IP will need to alert creditors to your wife's claim when he/she next reports, to manage their expectations.
I hardly feel that this is an IVA failure point, unless you guaranteed a dividend payment at a certain level, which was reliant upon you releasing a certain figure for equity.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
For further details contact me at
http://www.melaniegiles.com and view my IVA blog at:
http://melaniegiles.blogs.iva.co.uk