Was the marriage was eventually completed? If so, then perhaps the correct interpretation lies somewhere between our two takes on it.
The first three abbreviated words hold the key and generally "obt." is Latin abbreviation of obitum indicating the death of the subject, or in this case the discharge or failure of some aspect of the marriage.
My knowledge of Catholic marriage both in Europe and North America would suggest that perhaps, the notation is indicating that the marriage proceeded but only after and upon the necessity of obtaining the dispensation from the Apostolic which would overrule or negate the impediment to the marriage. In Europe a mixed marriage would not likely be sanctioned. In North America a mixed marriage would be sanctioned only after assurances had been made to the Priest that the children of the marriage would be raised Catholic and the spouse would be permitted to follow the Catholic religion and teachings. In either case, it is my understanding that if there is an impediment to a Catholic marriage, that impediment must be removed or otherwise satisfied - discharged - before the marriage was permitted to proceed.
As I cannot determine what country this entry relates to I cannot say anything more precise.
