I wouldn't be in it again because I wouldn't be married to him.
If he is in anyway remorseful and serious about making your marriage work, then he will instantly say "OK" when you tell him to go change the car. It could be done tomorrow.
Honestly though, you won't go in a car he had her in, but you will be a house where he (the one who really betrayed you) is. Car is not the issue lovey. Sorry you're being put trough this.