Hotaru no Hikari: It's Only A Little Light In My Life - Season 1 Episode 9 : What about tomorrow!? Never a love triangle 2010

There is a major revelation and the cat is out of the bag. The boyfriend is in Hong Kong and soon enough finds his girlfriend in too cosy an encounter with the manager. Then things become worse when the house-mates are found out and the manager's true feelings are revealed after Hotaru is rescued following her being locked in. The couple move in together.