My wife HATES my car.
One of my wife's oldest friends recently asked her what her secrets were for managing her finances and a good relationship.
She also mentioned she was struggling to find money to put a new roof on her house.
"For starters..." my wife said, "you spend $200 a month to do your hair and another $200 a month to do your nails. Stop that BS for a year and a half, and there's your roof".
We both agreed that being realistic about a potential mate (IE not assuming they will change) and realizing it's "a 2 way street", were big factors in not setting yourself up for relationship failure.