If the second car was not somehow made collateral or security for the first car loan (e.g. both cars securing the loan), then the second car cannot be repossessed because the first car's loan is in arrears.However, if you are separated you are still, as you note, legally married. That means that your finances are largely entangled. That in turn means that--if the second car is jointly owned by both of you--if creditors get a judgment against you as a couple growing out of the first car's loan (which could easily happen, since a repossessed vehicle will usually not fully pay off the loan; there is usually a remaining balance, which creditors could sue for), they may be able to then put a lien on, or force the sale of, some of your property, including the second car. This would take a lawsuit and court order, but is a possibility.If you're separated and have no intention of getting back together, you probably should consider divorce, to separate your finances, too.