Question: [Wednesday, 28th Adar 2, 5782]
I am marrying a Sephardi girl and would like to know if there’s any issue with me having a Sephardi Kesuba. I am Ashkenazi.
There is no Halachic invalidation present with you doing so, so long as you agree to obligate yourself to the details of the Sephardi Kesuba. Nonetheless, initially every individual should have a Kesuba according to his custom, being that there are subtle differences between them, and every individual should respect his custom. In the event that an Ashkenazi only discovered that he was given a Sephardi Kesuba after the wedding was over, then it is to be switched for an Ashkenazi Kesuba.
There are a number of subtle differences between an Ashkenazi versus Sephardi Kesuba, such as whether the word Deoraisa is to be written [as done in Ashkenazi Kesubos], as well as the sum of money that the husband is obligating himself to [which is normally more by a Sephardi Kesuba]. Now, for an Ashkenazi to use the Kesuba of a Sephardi does not contain any intrinsic invalidation, and it’s simply a matter of obligating oneself to what is usually a greater sum of money. This is only for the benefit of his future wife, and therefore there is no issue with doing so. Nonetheless, since there are certain changes from the normally accepted custom of Ashkenazi Jewry [i.e. writing Deoraisa, not doing all the Kinyanim of the Sephardi Kesuba, therefore, initially, certainly everyone is to use a Kesuba of their affiliation.
Sources: See Mishpat Hakesuba 1 p. 70; Hanesuin Behalacha Ubeagada p. 178