Whether or not she is paying for part of the instalment or not is not the point, but how much did she influence your decision on the car you are driving now? or your previous ride(s)??
Before the purchase my wifey will usually say something when I ask her for opinion .... but so far what I have bought were not always the exact models she prefered, but also not what she opposed..... except the OPC she uses now which is her first choice..... (so everytime she's angry with me over other matters, I will use the OPC as a shield, kekekekeee.....)