First, buy a new wedding ring! I mean, if you really really really want to use a band you have already you could but your wedding ring IMO should be special and something used for only that purpose. My wedding band is for more special and meaningful to me than my e-ring.
Second- sometimes things come as a set. Did he get a band when he got the e-ring? Or is a coordinating one available?
Third- what about complimenting his band? Is that something either of you would want?
Lastly- congrats!! Hope you have a wonderful wedding