Is there a real reason she wants 1 karat? I bought my wife a wedding ring and withing 4 years she was wanting another. But We were also talking about upgrading at our 5 year mark but the sale was to good to pass up. If all she wants to do is show off a ring then I would say no lets be reasonable. Do you really want to take a 5000-10000 dollar ring to work everyday just to scratch the hell out of it. That is what i would ask myself before you put that much on your credit, also if things didn't work out (god forbid) and she leaves you there are no real way to know if you would get it back or not. Just my 2 cents worth. Been married for 5 years now