Kedamono Dakara.

From Nakama:An employee at an excellent business real identity is actually since the family’s ninja bodyguard. Yet his master is like the dim-witted princess. The “princess” always clings to your pet while he works plus tells him “if you would like to you can become my wife.” He takes any possibility he can to get close. The particular ninja always thinks “I’m not your sex servant!” but everytime this individual sees the “princess'” phrase he is unable to resist plus continues to sleep with your pet night after night. To be able to separate the two of them, the higher episodes have begun to silently take action. Master and stalwart, this is a modern version of the kind of love story.