my wife and i are on the same page financially. i clear stuff with her i want to buy, same with her, if it's over 100$. it works well that way. we dont have credit cards, so i really dont have a credit worry problem with my wife or our finances. we pay cash for everything.
when i do sell a bunch of my gear, or any of her stuff, and set it aside for our own personal use, most times, as murphy will dictate, something ALWAYS comes up with the cars, the bills or the kids and forces us to make the right decision....use it on our family, NOT use a credit card or our savings for it. use the spare toy money.
yeah, it makes for not "having" all the extraneaous gear i did when i was younger, and she cant just up and fly to the southwest to see her family every 1/2 year and hang out with friends.... but, at the end of the day, we sleep soundly knowing we're not on a billing cycle thats compounding every month. if that means waiting longer to buy the toys we want, take trips, etc then so be it..by then, we usually talk ourselves out of it, or find better deals on it anyways.
prime example, my wife wanted a REALLY nice camera for like 3 years now...first it was 1800, and kept dropping....this year, it was 800, and she bought it...and a month later, it dropped another 100$. so she took it back and got the 100 rebate with the accessories that costco was offering. 3 years ago, spending 1800 on the camera, yeah, we couldve done it, but, 3 years later, THAT 1000$ stretched about where 1300$ would've gone..if you follow (gas prices, inflation, etc). making the right monetary decisions is truly tough, and, for all you young un's under 25 blowing up the credit cards on all kinds of new gear, i'd give this advice: be very careful with impulse buys.
in short, if your ol lady is bitching at you about buying shit for yourself and nothing for her, then its a jealousy issue....
but if she's telling you "hey, wtf, another guitar/amp/etc", you just spent 2k last week/month/day etc....maybe you should be looking at it.