A couple had been married for many years, and their son had gotten old enough to date. One day the boy brought a girl over to diner. The mother was thrilled with her son's choice and couldn't wait for the wedding. However, the father was upset and, eventually, the boy asked, â€œDad, why don't you seem happy with her. Mom likes her a lot.â€
The father explained, â€œNo son, there's nothing wrong with the girl. It's just that I cheated on your mother a long time ago, and the girl you've been dating is my daughter by that woman.â€
So the boy dumped her and found himself another girl. Again, he brought her home to the mother's delight, but the father again told him this girl was actually his half-sister. The boy lost his temper and told his mother what his father had said.
Furious, the mother shouted, â€œDon't listen to him, sweetheart! He isn't even your father!â€