Do I need to re do the nikah?
In the name of Allah, the most Beneficent, the most Merciful.
Kufr is to refute any commandments of Allah SWA, which is absolute and definite, or to have doubt or reservations about it, which has reached us through the medium of the Prophet of Allah Sallallahu Alahi Wasalam.
The condition of absolute and definite has been added, since the laws of Deen have reached us via two ways: one by way of Tawatur and another by way of Khabr Ahaad. Tawatur are those narrations that have reached us via the Prophet of Allah Sallallahu Alahi Wasalam, through a continuous and unbroken chain of narrators. From the time of the Prophet of Allah Sallallahu Alahi Wasalam until the present in every era, some reliable Muslims reported these narrations. Such things are absolute and definite and it is kufr, to reject and refute the validity of salah, zakaat etc. To jeer and degrade the Shariah is also kufr because these things are from the Quran and Ahadith Mutawatir. Aqaaidul Islam p.169 –p.170)
With regards to your question it is advisable that one takes precaution when it comes to doing takfir and calling another Muslim a disbeliever. Furthermore, you have stated in the question that you did not take the literal meaning but said these to explain a point to your wife.
Therefore, from the facts of the case the conclusion we can come to is that the aforementioned statement would not constitute disbelief or kufr.
However, I will advise to be on the safe side and also to put your mind at ease to re do the marriage. You will require two male witnesses or one male and two female witnesses. Also a new dowry will have to be set.
Only Allah Knows Best
Mohammed Tosir Miah
Darul Ifta Birmingham.