“If it is later discovered that there was no true marriage”
You can’t later “discover” anything, since the annulment is based on what your or your spouses’ thoughts and motives were at the time you were married. I suppose one spouse can discover it, but it Takes Two To Tango, so to speak...
I suppose ‘discovered’ is probably not the best word to use in this context, ‘revealed’ might be better. That is one of the reasons the process is so tedious. Although during the evidence phase of my annulment, which I had pursued based on my spouse’s lack of preparation/disposition, I did ‘discover’ that I was also completely unprepared and not properly disposed to receive the Sacrament, something I should have realized at the time but truly didn’t.
All marriages, even failed ones, are considered by the Catholic Church to have been valid. The annulment process requires proof that one or both parties were not properly disposed/prepared/mature etc. at the time of the wedding. There are many different grounds for recognizing a marriage as null, but the key question is whether or not something caused the Sacrament to NOT occur, because if it did not, then the marriage is not valid (if between two baptized Christians). Catholic marriage involves the spouses conferring the Sacrament on each other, it does not come from the priest, so if one or the other was unable to receive or give the Sacrament, then it does not attach.
If the Sacrament did not attach, then the two were not ‘joined by God’, and there was actually nothing to be ‘put asunder’, which is why it is not a ‘Catholic Divorce’, it is recognition that the Sacramental marriage never actually took place.
I’m not exactly sure what you mean by the ‘two to tango’ remark, but annulment only requires that one spouse was deficient in some way, and the marriage is null, because if one didn’t receive the Sacrament, neither did.
O2