I have a question regarding dreams. If a man who was getting married made Istikhara on the night before the wedding and in the dream he saw his fiancé saying to him "we don't have to get married". What does this mean? Does it have any meaning? I know dreams come from three sources. But the husband thinks the dream had some meaning and since they are having some problems he started to talk about divorce.

Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.

A dream after performing Istikhara prayer is not considered a sign for conducting a certain act or abstaining from it, but the conveniences provided by Allah are taken into consideration. Therefore, one should not rely on his dream.
The husband should try his best to reconcile the differences between him and his wife and to bring them peace, neglecting the dream.
Allah knows best.