Maybe the financial stress is spilling over, and making you guys more inclined to fight over other stuff? To me it sounds like you really need to sit down together and make a budget, so you're both on the same page when it comes to what bills need to be paid. Paying all those overdraft fees certainly isn't going to help anything... And once you know how much you can afford to spend at the grocery store, for example, take cash and only take enough for what you need.
I also think it matters how you approach the subject. If you start off by saying "I can't believe you spent all that money on stupid RC cars!!!" you will set yourself up for a fight. If you say, "Hey, I know we've talked about how we'd like to xxxx (buy a house, buy a car, go on vacation, whatever). I've been trying to figure out what we can do to work towards that, and I was wondering if you had any ideas." you might get a better response. Ultimately, you are probably both at fault, so sitting around blaming each other isn't really constructive.
