Extra Marital Affair
If man and women who are not married to each other come closer and show physical intimacy in anyway can be a sin, even unmarried. However its not zina. Since physical intimacy of any kind can lead to zina. Hence, it will prohibited on basis of sadde zariya. If you meant public display of affection by husband and wife who are marriee to each other then please see Discussion 50651 • Reply 50802