White gold alloy what is the better mixture?

White gold wears after about a year of usage and will need replating at up to 50 quid a time. Better of spending a little more outlay and going platinum as the cost and convenience more than makes up over the long run and they are much much tougher rings. I purchased my wife's ring from a company called Aardvark Jewellery (they have store, Etsy page and website)