Maybe Im stating the obvious but I feel like the author wants to draw a comparision between the MC and ML and ML's parents. The mother is (or was ig) beautiful with brown hair just like our MC and how it seems that initially the ML's parents loved eachother like how MC loved ML at one point. Idk I might be doing too much mental work but I feel like its not impossible.
Dear santa please make seong-ah more masculine, this is all I ask for..