BookBarbarian
Expert Long Rester
Getting mad might not be the proper term. I politely explain my reasoning. The monk agrees with me and says that the dm has final say but the cleric doesn’t like being wrong so she repeats herself over and over and sometimes starts like she’s about to cry.
Ah here we get to it.
You are under no obligation to psychoanalyze this person's "Not being able to be wrong" problem. However, it will be very difficult to continue DMing for this person if they can't rein this behavior in. It's just too disruptive.
If it were me I would have a private conversation with this person asking about the emotional behavior and why they feel they have to be right all the time, point out that they are among friends, and explain how it is ok to be wrong, in fact it's very interesting to be wrong sometimes as Characters that are never wrong are very boring, whether in books, tv, movies, or RPGs.