Hi hol and welcome to the forum
Potentially you can propose an IVA without your wife's knowledge, but I would not recommend such course of action. Your wife would undoubtedly be a great support to you during the proceedings, and to do this without her knowledge is likely to cause difficulties for you.
If you own a property which has equity in it, and is jointly owned, then your wife will have to give her permission to any future raising of funds - which creditors are likely to request.
And notwithstanding whether you wish to inform your wife or not, your IP will need details of her own income and expenditure to be confirmed, to ensure that you are making a fair contribution towards shared expenditure.
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