Natsuyuki Rendezvous

Ryosuke works part-time as a florist. He has bad eyesight, a pure heart, and a secret crush on the store manager, Rokka. Unfortunately for him, Rokka swore off love 8 years ago. But when Ryosuke goes up to her apartment on the second floor, he runs into a good-looking half-naked man. At first upset, he learns that this isn't Rokka's live-in boyfriend; he's the ghost of her late husband, Atsushi. She can't see him, and Ryosuke decides not to give up on her, even with a dead husband standing in the way.

Synopsis from Anime News Network