My wedding ring is a platinum band. I had never previously worn any ring so had no fixed opinion on what to get, etc.
When we selected the engagement ring, she wanted one like her mothers which is platinum. When the wedding rings were being selected, hers was to match the engagement ring and mine was similar to match hers.
So, my wedding ring ends up being based on a choice my mother-in-law and/or father-in-law made over 50 years ago. If your fiancée has a definitive view on the style and form of her engagement ring, it may affect the style and form of your wedding ring.