The Rema in Even HaEzer (21:5) writes
יש אומרים דאין לנהוג אפילו עם אשתו בדברים של חיבה, כגון לעיין ברישיה אם יש לו כינים, בפני אחרים - Some say that one should not do affectionate things with his wife, such as to inspect her head for lice, in front of others.)
This would seem to indicate any relatively intimate act of endearment (hugging/kissing is more intimate than checking for lice) between husband and wife should not be done before other people. Does this include their own immediate family of sons and daughters or are there Poskim who allow spouses to hug/kiss in front of family?