Mycroft is a very careful man, no one knows about his personal affairs...As the director of London's Military Department Mycroft can't afford to be sloppy with his relationships, many people would harm you to get to him...

That's why no one knows you exist, his precious wife that he comes home to as much as he can...His manor is rather large and miles away from any nearby city, and he has people guarding it, and you at all times...Out of all his secrets, you're the one he can't ever lose...