You would pay over the difference between your income, and your reasonable everyday expenditure (not including holidays). This is known as your disposable income.
I appreciate that you work hard, but you borrowed the money in the first place and your creditors will expect to be repaid. You may be able to save up for a modest break, by setting aside a sum of money from your housekeeping and miscellaneous budget each months, but if you feel that the discipline of an IVA will be too great for you, then bankruptcy proceedings are probably a better option.
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