That is so sweet of your fiance! But here's hoping he bends just a little, since matching is hard, especially when yours has to go with an engagement ring.
My wedding band is a 4 3/4, and it's plain. His is traditional, has three flush mount bezel set diamonds, but is otherwise plain. It's like this, only the diamonds are larger and it's gold:
I'm glad we went with plain bands, because 18 years later the style doesn't look dated. Except that they're yellow gold, and now everyone is getting white gold or platinum.
The most important thing: make sure his is engraved with the wedding date so that he won't forget your anniversary.