The tradition of  newlyweds  going on holiday together  originated in the early 19th century in Great Britain. This concept was taken from the Elite Indians, in India. Wealthy Indian newlyweds would take a "bridal tour", sometimes accompanied by others, to visit family members and friends  who had not been able to attend the wedding.  The tradition  soon extended widely to the European continent.
The term "honeymoon" originated from an old northern European custom in which newlyweds would, for a month after the wedding consume a daily cup of mead (a brew that is made from fermented honey) to ensure happiness and fertility. The word “moon” is derived from the  inevitable waning of love and affection between the couple like a phasing of the moon.