I don't want to give the wrong advice here, but I've been in your wife's shoes. Her over the top and inappropriate reaction is not ok, but I guarantee there is A LOT of pain behind it. And the pain probably has nothing to do with the money. The opposite of love is not hate, it's apathy. Her actions are not ok, but she is acting this way because she is deeply, deeply hurt over something. What do you think the money might represent to her? Do you think she sees it as reflection of your value of her? Why do you think this hurts her so badly? It might make a world of difference if you could do a little digging. If you think it's that she views this as an assessment of her value, you could say something like "I am so sorry you are feeling this way. Maybe it feels like this is a reflection of how much I value you, but I promise it is not." Again, not excusing her behavior. I'm telling you what would have helped me a TON when I was acting out.
DH's validations without thought just came across as patronizing. I needed him to see why I was acting like a raving lunatic. What his part in it was. Simply saying "I'm sorry you feel that way" tends to discount why she may be acting that way. Saying " I'm sorry you feel that way. If you think this is because I don't value you/your contribution to our family/that I'm trying to cheat you/whatever" means that you might get it. If you hit the nail on the head, there's a good chance she will de-escalate and soften.
