Not the easiest of answers - you could be looking a regional nuances in dress and about 100 years of changes in fashion. The classic 'couple' is this one :
http://en.wikipedia.o...ki/Arnolfini_Portrait
Anyone who could get a portrait done would be seriously rich, and the period you are looking at is one where people were either rich or poor with a tiny but extremely powerful ruling class.
Titles such as 'Lord' usually had duties attached to them that implied you could afford to do them eg provide a number of fully equipped soldiers to the king; pay taxation at a certain level for a certain area of land.
Simplest answer - at this time the only social classes were the well-off and the workers.