Ah, so you were both baptized Catholic and married within the Church. I can see now why you would feel as if that would cast doubt on the tribunal’s verdict.
That said, for any Sacrament it boils down to form, matter and intent - and with marriages, a tribunal would look at all three.
Matter: You need one man and one woman who are not in a currently valid marriage in order for the Sacrament to be valid.
Form: The method used to administrate the Sacrament. There’s a bunch of canon law stuff about this, but 3200 character limits means I won’t post it here.
Intent: The one man and one woman must intend on a Sacramental marriage. Intent could be impacted by several things, such as lying about being open to children, lying about past history, being forced into the marriage, being in an abusive relationship where you feel trapped, and so on.
In my opinion, this might be where the tribunal was looking. You said earlier:
It’s possible the tribunal may have thought that neither of you at the time understood the ramifications of marriage, and perhaps the intent for the Sacrament was missing - which would invalidate it. Especially if you weren’t married for a long period of time.
Of course, this is all speculation on my part. Obviously I wasn’t a member of the tribunal. But based on what you’ve said thus far, I wouldn’t doubt their ruling.
Anyway, I’ll stop posting about this now, as it’s probably none of my business in the first place.