Most of the time, this has to do with the outdated style which a ring carries, or simply the way the champagne diamond wedding ring now looks on the finger. If sentiment is the only thing that made you keep your old wedding ring for this long, it may be high time you went and changed it.
There is nothing wrong with being assertive about the things you like, especially when talking about it to your life partner. The main point to get across is this: the old ring does not suit you anymore, and you want to change it.
This need not be just about “fixing a problem”, where you have to wait until one of the prongs comes loose, or a side stone falls off, or something else of the sort happens. Head to a jeweler and ask them about the possible changes you can make in order to have a diamond-studded ring that suits your style and personality. Draw up something you like, and think long and hard about how it would look on your finger.