Yes - as you need to make an accurate disclosure of your circumstances. But you have no legal obligation to disclose the IVA to them, so long as you are aware of their income level.
On the other hand if the relationship ends, then you will need to complete a new income and expenditure form to show your revised position. If this results in you not being able to afford to service your IVA, you will then need to consider whether a formal variation of its terms is necessary.
Regards, Melanie Giles, Insolvency Practitioner for over 20 years.
To have me propose an IVA for you, please visit:
http://www.melaniegiles.com/ivaEnquiry.asp
See customer feedback at:
http://www.iva.com/iva_companies/IVA_Advice_Bureau.asp