Realistic/bittersweet romance manga recommendations

Even as a kid, I was a big fan of Nana and Paradise kiss; I really love it when a romance story is not perfect, the characters are layered and flawed, and the end is not the simple and predictable "they lived happily ever after" out of a fairy tale.

I recently read Bitou Lollipop and I really liked it, though the characters were a bit uncomfortably young at the beginning for my taste. Another examples from the top of my head are Kakafukaka, Watashitachi no Shiawase na Jikan and I am in the middle of reading Solanin.

I am looking for manga recommendations along these lines.

Webtoons (or anything readable really) are also fine by me, Muse on Fame for example is still ongoing but I like it so far.

Thank you in advance!