why would you want a bigger wedding ring?

I love bling.

The more expensive ring does not have the sentimental value of the original ring. If you want a larger ring and you can afford it go ahead and buy any kind of ring but not a substitute of the original wedding ring. The original one will be a reminder of all you have done in life.

Some are completely satisfied with a simple wedding, and some aren't. I has nothing to do with not honoring a marriage, it's about someones taste in jewelry. I've been married for almost 12 years, and all I wear is a plain platinum wedding ring.

Lots of reasons. It also depends on who is suggesting the "bigger" ring. If the husband is suggesting it, it may be that his economic circumstances have improved and he wants to give his wife a more impressive ring. Or maybe he wants to impress others (friends, family, co-workers) by giving her a fancier ring. Perhaps the couple together has decided that they can afford a new ring and want one that reflects their current economic circumstances. Maybe they have gotten a new ring to commemorate an anniversary or a special occasion. Perhaps the wife has decided that her friends or family have "better" rings than she does and so she wants to trade up to something fancier. Yes, some of those reasons may be somewhat shallow but it is up to the couple to decide what fits their tastes and circumstances.