I think you just interpreted yourself

Additional point - remember that everyone in a dream is, in some level, a projection of some part of yourself. So you could also ask yourself the following questions...

"What in my mother-in-law do I dislike? How do I see that in myself?"
(This is addressing the psychology of negative trait projection, where we see and react to negative traits in others that we subconsciously dislike in ourselves.)
When looking at negative traits depicted in dreams, typically what you may want to consider next is -
"How can I take these traits and make them positive?"

"What emotions came out of the return of the money? Did it make the tension feel resolved?"
-- This can give perspective on the significance of the event.

"How did my ex make me feel devalued?"
(This is addressing the fact that your ex was symbolized as the coins, which are typically seen as a form of minimal value currency.)
Similarly, you might ask -
"How do I feel I devalued my marriage?"

Was there anything said in the dream? This could reveal some significant point of view as well...