My husband and I are now on the same track when it comes to money, but it wasn't always thus. Conflicting attitudes and goals were a constant source of stress and acrimony.
The best I can describe it is that before my husband's ADHD diagnosis and medical treatment, money was more of an abstraction to him rather than a reality. He would say that he didn't care about money, but the evidence clearly showed that he cared about the things it would buy. If he wanted a new gadget, he bought it. If he wanted a new book, he did the Amazon one-click. There was little thought between want and buy and little consideration for what might happen between now (when money was coming in) and not now (when sickness, unemployment, or retirement meant it wasn't).
My Depression-era parents had demonstrated good money-management principles for their seven children and, thanks to a meager journalist's salary most of my life, I had ample opportunity to put those stretch-a-dollar principles into practice. As a result, I didn't understand my husband's careless attitude towards money. Finally, I realized that there was no thinking; there was just impulsivity and no regard for the future or even short-term goals. Money was simply frittered away to impulse purchases, traffic citations, late fees, and, well, you get the idea. Then we learned about ADHD and its common challenges around money. Even with the diagnosis, though, we did not have a clear path towards better joint financial-management.
That path would have been much clearer if we had been able to read ADD and Your Money, by