This is from
WeddingDetails.com under Roman Catholic Traditions.
*Candles
The use of the Unity (memory) candle is often discouraged. (However, each parish priest will make suggestions on this; follow his direction.)
The United State Conference of Catholic Bishops has deemed the text of the symbol of the candle as faulty symbolism within the ceremony. If a Unity candle is desired, it is often suggested to build a ceremony within the rehearsal dinner celebration. *
A Candlelight blessing has been used in both Catholic and Protestant churches. It is acceptable because of the spiritual context of the blessing. In the Catholic tradition, the candle (flame) is a symbol of Christ, the light of the world. The Scriptures given confirm this concept, and are cause for reflection among the guests.
*The Unity candle that is lit by the bride and groom often symbolizes their separate lives being joined together, thus extinguishing the separate lights of the side candles and the combining to light the single large center candle. The Candlelight Blessing is a confirmation of that symbolism, and often follows the lighting of the Unity Candle. *
I’m not exactly sure what the reasoning would be from the USCCB but I did read something about how decorative candles are not allowed and that the number of candles near the altar signifies something specific, although I’m not sure what. But this was just from a two-second google search, so I’m sure there’s a good reason somewhere. Happy wedding!