Besides control of the thermostat, spending habits may be the biggest cause of arguments for couples. In the history of the world, I don't think there is a person in a committed relationship who didn't believe their significant other blew their money on garbage.
Of course, everyone can always justify spending money. I think my wife spends too much on clothes and bags. She counters (rightly) that she needs to dress well for her job. She thinks I spend too much money on computer gear and iTunes. I counter that I need the best equipment for writing and schooling our children on the Beastie Boys canon. Finger-pointing and shouting ensues, ad nauseam. No one wins. Guys will always react defensively if you accuse them of spending too much because they think you are frivolous, and vice versa.
The best way to avoid this argument is to be open and honest about what each of you spends. Whichever one of you keeps the books should present a complete report of all the household expenses and monthly bills so you can see exactly how much discretionary income you can spend. Work with an accountant and financial adviser to make sure you're saving enough for education and retirement. Set up a special budget to save for big-ticket items like vacations or a new car. Once you make sure you've taken care of the important things, you can look at the numbers and see what's left over. Maybe the occasional purse or new iPod isn't such a crime after all.
Asking your husband to spend more time with you