Couples should choose the time and place to show each others love. Physical intimacy isn’t the only way to show one’s affections to their partner. It can also be shown through expressions or through values.
Some of my friends consider physical intimacy in public natural, which in my opinion can be either true or false. True, because lovers would also like to experience showing their affection to their partner by physical contact. False, because other lovers keep on overdoing it. I find it really awkward to see others kiss, but I find it sweet to see a couple holding hands smiling toward each others gaze.