When you invest your time, you make a goal and a decision of something that you want to accomplish. Whether it's make good grades in school, be a good athlete, be a good person, go down and do some community service and help somebody who's in need, whatever it is you choose to do, you're investing your time in that.
To love a woman for her virtues is meaningless. She's earned it, it's a payment, not a gift. But to love her for her vices is a real gift, unearned and undeserved. To love her for her vices is to defile all virtue for her sake - and that is a real tribute of love, because you sacrifice your conscience, your reason, your integrity and your invaluable self-esteem.