I don't want all the blushing and embarrassing talk. I want to read a Manga about deep love, maybe over years wäre the people just have these relaxed smiles when they see each other.
I don't have a good exmple at the moment so i hope you understand what i mean.

Preferably between adults but without much smut or ecchi.

umm Bonnouji if you haven't tried it already. Not really my forte, so I have no more suggestions.

Edit: I also remembered a romance I found really touching. My Boo, its a webtoon if you can handle that. But it undoubtedly focuses on their incredible emotional connection, if bittersweet is okay.

Also, two more which didn't let awkward situations make me feel awkward reading was Horimiya, not about adults, but high school students and Kimi wa Pet could have been better researched, but the atmosphere is pretty good. Not sure if they're what you're looking for, and they're both pretty high regarded so you may have heard of, if not read them both before xD

Angel Sanctuary: Although Setsuna and Sara are teenagers, their romance is far more deep and serious that most part of shoujo mangas. You won't find the blushing and childish side of most part of the stories of the genre.

Hanasakeru Seishounen: Kajika and Lee Leng have a deep bond that doesn't fall in the cliché relationship couples use to have in shoujo manga.

Now, if you don't mind Shounen-Ai/Yaoi, then Blue Sky Complex is exactly what you're looking for.

[img]https://i.imgur.com/6MBFpsv.png[/img]
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