Engagement Ring

So, in April Kevin (my fiancé) gave me an engagement ring. He thought it was sterling silver but I found out later it wasn't. How did I find this out? Well, the ring started turning a copper color and turning my finger green.
Then, in June when he came to visit we bought matching rings. They we're so cute but one day at work I lost the stone to it. (It was a $15 ring) I was upset so I started wearing the other one. My finger is still green. =/
The other day I showed Kevin this ring. It was a Tiffany's knock off, meaning sterling silver but cubic zirconium. It was beautiful, absolutely gorgeous and Kevin said he'd buy it for me!!! I'm so excited!
I'm the type of girl that would rather have a fake ring than a real one. Why you ask? Well it's simple, I won't feel that bad if I lose the ring or something happens to it. Anyways, here's the picture of my ring:

Gorgeous isn't it?