A landscaper and a photographer fall in love. This is gentle and sweet.
Other commenters have suggested that the parents in this might be the couple from "Kare no Shousou to Koi ni Tsuite" who love each other so much and go on the cruise! That would mean they're still together at least 15 years later. One is called Watabe, but the other goes by Seiji. The names in the other story are Watabe Kazumi and Yajima Hideki, so unfortunately, I don't think it's them (unless there is a kanji reading difference, maybe?). In the other story, Watabe was also the middle child with a younger sister. Here, he's said to be the youngest sibling (which is why he's such a young dad).
Kimiiro Eden