I assume that your IVAs are mutually reliant, Jol, ie you pay one combined payment and all of your creditors receive the same dividend?
If you separate, you will be presumably be funding two sets of housing, bills etc, and your husband would have to pay you child maintenance on top which would become part of your income. So the figures could change quite dramatically.
Do you own any assets of material value - such as a property with equity or other items which would be affected under bankruptcy proceedings. If not, then this could well be a better option to enable you both to make a fresh start.
Regards, Melanie Giles, Insolvency Practitioner