Aside from whether LW2 should be thanked or was wrong for trying to keep it a secret, I just find it really weird that LW's son told his wife that he bought the car on his own. Does she not wonder where he suddenly got the money for a whole new car? Like, maybe they have separate bank accounts, but I would still expect some shared knowledge of the state of each other's finances, especially since they have kids. If I were the wife in this situation I would be really weirded out and worried that he suddenly had a ton of money I wasn't aware of.