People believe what they want to believe.

She believes in this way because, then, she doesn't have to show gratitude or feel the burden of responsibility toward you.

She lacks empathy. You probably didn't ask her to help you with chores when she was younger and did everything for her feeling like a hero.

Love yourself more, so you have less need for love from others.

You did what you thought as the right things to do and you had the opportunity to do them. Count as a blessing.