Having the car as security for the loan would make things more clear-cut, but if you took out the unsecured loan during the marriage seems like that would still be marital debt, so still split between you. So you could probably still make a deal to keep the car and the loan, give her a couple hundred dollars and call it good.
If you really need the lien, you might check with your bank or credit union to see if they'll make you a loan against it.
But now that divorce is in the air I think you need to be really careful about tracking financial matters like changing titles or incurring new debt so it doesn't look like you're trying to manipulate things to screw her over.
She's probably also entitled to half of the furniture you bought, and you might have some arguments about the $7,000 in marital funds that you put into your house. The house is probably still your separate property, but she may lay claim to some value based on that--maybe just half of the money put in, but I could also see her claiming rights to the resulting increase in value/equity in the house. I'd mention that to your attorney, seems like that could get a lot stickier than the Jeep issue.