Caged Slave (2007)

Blurb:
When Tsukasa meets a mysterious man in a hotel lobby, and ends up spending a maddening night of pleasure with him. Afterwards, he accepts to meet him again in the same room the following week, despite the fact he doesn’t even know his name. As their secret encounters continue, he finds himself falling in love and is worried that it may not last. Simultaneously, he’s scouted by a business-talent head-hunter and receives an interesting work offer. But when he goes to meet them... his new boss is none other than his secret lover!

Source: www.anisearch.com/manga/1416