could there be a harem ending later where you are married to more than one person there could also be a ending where you have no one 

Multiple endings, my good sir/ma'am/apache helicopter, think of that as you will. Although at this point in the story, there's absolutely no Kung-Fu to do on the story for the MC to end up with no one, unless you want to end up with a nonsense ending.

I can't wait for the harem ending. I love all of them.