Hi chillimaiden and welcome to the forum
You generally have to pay your creditors in full from windfall monies, together with all outstanding costs of the arrangement. The supervisor will not charge you more fees for settling early, indeed your husband ought to get a saving for his final year fee.
Put the money on a high earning deposit account for now, and ask the supervisor for a settlement figure. As the windfall is your husband's money, then he does not need to give you any of it - but I am sure that he will! As the windfall is not yours, you can offer a lower figure, but I would keep it at the level of the dividend you origianlly pledged.
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