Hi! I have three manga I read before but I just can't seem to remember the names.
the first manga is about a boy being able to separate from his body when he is dreaming. He goes to visit his ex girlfriend?
the second manga is about a demon king who everyone is afraid of so they send maidens to his island. but he's not a bad person, and he makes a country from the island.
the last manga is about a guy who falls in love with a the number one hostess and he decided to enter that world?

Thank you for helping.

#2- Shina Dark

Sorry, I don't have a clue on the other two.

The first one is Yuutai Nova:

http://www.mangaupdates.com/series.html?id=13422

The second one is Shina Dark:

http://www.mangaupdates.com/series.html?id=11939

I think I've read the last one before but I can't remember what it was called.

wah! thank you! you guys got the first two right! it's been racking my brain remember. I think for the last one, well I read it 1-2 years ago. and last i read it, there was only about 2 chapters out?

It took awhile but I think I've found the last manga that you were looking for.

Kurofuku Monogatari

http://www.mangaupdates.com/series.html?id=11670

Found then