Kimi ga Nozomu Eien, Koi Kaze Recommendations
Though way opposite story lines, both involve very deep romantic relationships.
Both are EXTREMELY depressing but potent romance series. They each have very human characters and stories, and have factors too.
Kimi's circumstance would probably happen more frequently in reality. It also is much more bitter than sweet.
Koi Kaze's theme is much more serious and is handled that much more seriously. However, it is a bit easier to watch, and ends much, much better.
For its dramatic content of everyday life
Both series contain the theme of love that is presented in a more mature and realistic way than typical romance series. In other words, both series are serious love stories that are not the typical puppy crush or love at first sight types.
Both series has many emotional moments but also some comedy moments as the main protagonist deals with the feelings he has for the main female character.
Both series are sober and built on drama as well as guilt that presents romance in a mature way.