Why should my income have anything to do with how my property is divided?

Given your scenario, it is more likely that you could recover any property that is given to your spouse, since you have a greater income. You can more easily replace a car, for example, if your spouse should end up with it, than your spouse could, if he or she earns significantly less. This focus is about balancing the equities. Remember, "equitable" does not mean equal.