I really want a manga like watashi no shounen. It doesn't have to be older female and younger male, but I want to find a manga where the main characters are drawn to each other even though they shouldn't be. No shounenai/shoujoai/yaoi/yuri/ecchi/harem but everything else is ok.
Thanks 😀

Blood Alone is another manga with a large age gap. It's a really pure and an awesome read. I get the feeling it's similar in that respect to your example, and their relationship would be frowned upon by those around them if it became anything more than that of a guardianship - which it is constantly threatening to do. It's also probably one of the best non-cliche vampire stories you could get.

Umm 14-sai no Koi has a really brilliant and hilarious secondary, ambiguous student/teacher romance. It's not the main focus, but does get plenty of time to explore. The main pair keeps their relationship secret too, but not really because it's "forbidden". The art is clean.

In general, I avoid the forbidden romance trope so there's no more suggestions. In most cases, it's used and exploited to have far too much angst and drama. These two which I've recommended have drama to a palatable degree, but put more emphasis on the characters and their interactions.

Also something like servant and master (Traditional thinking)?
[Kagetora](https://www.mangaupdates.com/series.html?id=590)

American Ghost Jack - Ghost/human relationship.

Palace Meidi - Master/servant relationship.

Transparent Cohabitation - Ghost/human relationship.

Ojou-sama no Untenshu - Master/servant relationship.

Dare mo Shiranai 29-nichi - Ghost/human relationship. One-shot.

Joou no Hana - Master/servant relationship. The ending is terrible but the beginning is really good.

Let me just drop this here...

The Duke of Death and His Black Maid Master/servant + added supernatural powers
Niehime to Kemono no Ou human/demon
Hime Koi oneshot master/servant
Haru no Noroi Ummm

Girl with her deceased sister's fiancé

Colette wa Shinu Koto ni Shita Human/God
Momoyama Kyoudai Siblings

not really, but they always thought they were brother and sister

omg I didn't expect these many..well I better get started with the readings! ? thanks for all the suggestions ?

Debu to Bijin

Sachi-iro no One Room (kidnapper/kidnapped)
Maou no Ore ga Dorei Elf wo Yome ni Shitanda ga, Dou Medereba Ii? (master/slave, but wholesome)
Tsubaki-chou Lonely Planet (older guy/younger girl)
Jibaku Shounen Hanako-kun (ghost/human, only hints of romance for now)
Devils Line (vampire/human)