You'll see couples holding hands, or hugging or with their arms around each other but deep, intimate kissing in public is not common.
Spanish men and women greet each other with kisses all around (including man to man).
Belgians - men and women - may give friends and relatives a kiss on the cheek and everyone else a handshake.
Couples can openly show their affection for one another, but mainly keep the more intimate stuff private.
But I was single long enough in Spain to notice some differences when it came to the European and Spanish women compared to their counterparts in the states. Life in Los Angeles (LA) is not an accurate representation of the US as a whole.