My wife has the same instant gratification problem I do except with different items, usually crafting-type items. Her purchases are usually much less than mine, but often more frequent. We recognize that we both have the same problem, so we don't complain about it in each other too much. On the other hand, we don't seem to be doing much to solve our problems, which is probably why we never have any money to speak of.

A similar place where we do have a problem is that my mother tends to be waaay too generous. My wife always wants me to refuse such generosity. I find this to be nigh impossible, and my wife can get very angry at that. Of course, she has no better success rate at it than I do, but bringing up that fact only makes her more mad.