When buying a car with someone else, whether or not you are married, the dealer will ask you how the title should read. It is important to:
1) Get your name on the title if you are going to be paying on the car loan or using your money to buy it.
2) Use the word AND on the title. Examples : John Smith and Marie Smith ; Juan Lopez and Maria Lopez
as the owners on the vehicle's title.
Surprisingly it is not because of proving assets in court. Although it will help when they try to claim the car as entirely theirs, it is also to stop the other person from selling the car without your permission. For some reason the person you are with who was kind and trustworthy turns into someone completely different during a divorce or breakup. The person who never would have thought about taking anything away from you now many be hiding money so that they have to pay you less, or taking things simply to hurt you. No matter the reason you do not want to give them ample ability to sell the car without your permission after a fight/breakup and before a court order on property possession and control.
If the word OR is used (John Smith or Marie Smith) then either party can transfer the property.
If the word AND is used (Juan Lopez and Maria Lopez) then both parties must sign over the property.
Protect yourself from the very beginning. When buying the car always have the title use the word AND.