I agree with selling the SUV and paying it off, even though you won't own it. You'll feel better, your credit will be better, and you will save a ton just based on your improved negotiating position.
That said, I got married a year ago, and while we have a joint savings account, we keep separate checking accounts for a reason. She knows that my money is my money. Since half the time it gets spent on her (dinners, rent, travel), she's okay with me spending it on me too. Still don't have kids though - that may be the difference
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Good luck either way. I actually feel like being frugal is worth something. Run the RX-7 into the ground (although driving one of them for the gas mileage is pretty funny - mine used to get about 16).