Wholesome story

http://www.mangago.me/read-manga/this_witch_of_mine/?RJcl
you'll definately love this, its a happy ending I guess? but the PAIN, its perfect for you ~ 1000% reccommend this!

http://www.mangago.me/read-manga/my_broken_mariko/
man, this is sad, you'll enjoy it i believe. its about the after affects of suicide

http://www.mangago.me/read-manga/3_level_combination/ its made by the same creators of the manhwa you mentioned so you may like this

http://www.mangago.me/read-manga/oshi_no_ko/
beautiful visually and plot-wise, its very good but ongoing

http://www.mangago.me/read-manga/the_cradle_of_the_sea/
not exactly bittersweet, but its a beautiful sea adventure story

thanks a lottt!! =3