Abusing the Caregiver

I received yesterday a proposal from a family member (not directly related) to offer me assistance in alleviating the unfortunate byproduct of my loving care for Mary, namely my celibacy. As the shock is settling down and the disgust settling in, I am reminded of the other incidence of blatant abuse when Aunt Angie accused me of being lesbian, since I was so affectionate with Mary. I wonder, is this common? Why do some family members seem to feel a need to take advantage of or abuse a caregiver? Is it that someone who spends most of her hours serving another seems to be on a lower status level? Do I seem worth less because of my lack of giving back to society in the traditional ways so that people feel they can dump on me or treat me in some way which most clear-minded people would surely recognize as inappropriate? I've heard of shooting the messenger, but abusing the caregiver? I can only shake my head and hope that these people don't make a habit of treating others this way. And thank my lucky stars that my own head is screwed on right.