I'm looking for a romance manga where a guy who thinks he can do fine without anybody suddenly have someone some into their life. Doesn't have to be shoujo, it could be BL too. No shounen.

how bout Kanata Kara- its a great one!!! even though its a bit oldish...
and also Tail of the Moon and Mujuuryoku Shounen the male leads are a bit like that...

hop i helped!!! 😀 😀

omg!!! just noticed this is my 200th post!!! yay me!!!

oh please do click this!
The sweeter the apple, the higher the branch. The quieter the fart, the nastier the smell.
GUESS WHO??

Gakuen Alice
Vampire Knight
Shinshi Doumei Cross
Imadoki!
Childs Toy

The rest... I'm unsure if they're like that, but i thought i'd throw them in ^^;

Watashi ni xx Shinasai!
Special A
Gokusen
Fruits Basket
Kill Me Kiss Me 2nd arc is a little like that... not really