I gave DD1 a name that could easily have been hyphenated but wasn't. It was a combination of her paternal great grandmother's name and the name of one of my favourite aunts and it was intended that the two names would be used together. Think of a fairly familiar name combo like Anna Maria and you will understand why using both names would have been the obvious thing to do.
However, exMIL seized on the first name and ignored the second one and the rest of the IL family followed her lead, including exH, who disputed that we had ever intended to use both names. It was impossible to fight the tide.
But now, years later, it gives me enormous satisfaction to see that DD uses her full name professionally, and hearing her full name called out at her high school and university graduations was a truly wonderful experience for me.
You have my sympathy, @DorisDances. Names mean a lot, especially if you used the naming opportunity to honour someone you loved, or even if the sound of the names together was something you loved when you chose them.
Fwiw, I have never been to a wedding where only the first names were used at the vows. It has always been the full whack, as in "Diana Frances" and "Philip Charles Arthur George" 