My very perceptive sister-in-law has picked up a discrepancy between Soulmate and I, semantically (or etymologically) speaking: I have been spelling our new daughter's name with two "A"s instead of one "A" and one "E". I decided long ago that we would most likely end up calling her "Katie", so I thought her full name should start with a "K", not a "C", but didn't pay attention to the vowels.
I'm generally not one to run to the court of public opinion in private matters, but this being a life-long appellation, I decided to google the various options. It turns out that Catherine and Katherine are about equally popular, with the K version slightly more popular, so that's a relief.
Katharine has in its favor an association with an Oscar-winning actress and three Shakespearian characters (from Henry V, Henry VIII, and Love's Labour's Lost), and it was favored by the Romans. Katherine was favored by the Greeks, and is overwhelmingly favored by Americans, Germans, and Brits.
Soulmate plays the trump card: since our last name is often misspelled, which given name is less likely to be butchered? The answer wins the day:
KATHERINE it is.