It's about a boy who can leave his body. And he runs into a girl who has the same powers. He was stalking his ex girlfriend, but realized everyone has moved on with their lives but him. So he searches out the other girl who can leave her body. I think there were 10 or so chapters scanlated.

I believe the manga you're looking for is called Yuutai Nova

Some guy lurking, but not doing it very well

Thanks. That's the one.