The Aesthetic Movement typified by a non-corseted figure was not ever really embraced by the fashion conscious women of the day, except at Tea Time. This was a chance in the middle of the day to have tea with lady friends in a state of partial undress. In the 1890's this became another place to lavish detail and expense on another gown.
This one was made as a wedding dress. There are many examples at the MET of Teagowns, and the V&A has several that are just amazing in their details with jewels, beetle wings, and beads.
These dresses can be worn over a corset, but it isn't required. Much like the later Teens dresses the inner bodice is boned and gives shape and structure to the rest of the dress.