You shouldn't resent your partner's parents.
Jill is envious of her husband's parents because they are rich.
Jill wants to handle her emotions.
Jill realizes her husband's parents didn't do anything wrong and thus gets over her emotions.
Jill keeps resenting her husband's parents for not having any financial problems.
Jill clears up her resentment and builds a better relationship.
The resentment keeps spoiling the relationship over time.