Dear Rabbi Simon
If neither one of us signed the ketubah is the marriage a valid Jewish Marriage?
A ketubah must be signed by two witnesses (who meet certain halakhic criteria).
Since it essentially lays out the husband’s commitments to his wife, in some circles it is customary for the hatan to sign the ketubah as well. However, this is not required and a standard Orthodox ketubah does not call for it either. (It is, however, important for the groom as well as the witnesses to understand the fundamentals of the ketubah.)
If your wedding was conducted by a competent Orthodox rabbi, I am sure your ketubah and your marriage itself is valid.
Best wishes and shanah tovah
Rabbi Rashi Simon