Now my father-in-law is living, and my husband won't tell me. Instead, my in-laws will tell me, will you go to my father-in-law's birthday?

Since my in-laws told you, of course I still have to attend. You don't need to be dissatisfied with your husband. It is very likely that he won't remember his father's birthday, because men are careless and sometimes don't even remember their own birthdays, so go to my father-in-law's birthday party happily! The old man also hopes to be reunited with the children on this day.