www.iva.co.uk

Is it possible to open an IVA in just my name, in order that my wife can keep her credit cards, and also not to impair her credit history?

Hi
Yes it is
However you will have to include any joint debts but your wife will still have to make full contractual payments on these debts.
Her credit status may,and probabaly will,be affected by you entering into an IVA
Regards

And your wife will need to ensure that she can pay her committments from her share of the disposable income with no contribution from yourself.