Dear Queenie,
My husband’s father always remembers both our birthdays with cards and cash, but he always gives my husband more money than he gives me.
Queenie, I don’t get it (literally). Do you?—Short-changed daughter-in-law
Dear Daughter-in-law,
I can think of several possible reasons: His son is a blood relative, you are not. He has known his son longer than he has known you. His son is a man, you are a woman. If his son is considerably older than you are, the age difference may be the reason. He thinks of his son as the head of the household, supporting you, and therefore needing the money more. Etc., etc., etc.
If you really want to know, try asking him – as sweetly and non-confrontationally as you can manage.