I kind of fell into teaching by accident. There was simply no one in my area teaching Kunst des Fechtens the way I felt it should be taught. I had joined a really good organization (the AES), but the person who was heading up the chapter had to move away. So I trained hard and took up the the job.
My motivations are for teaching are the same as for pursuing the Art as a student: The European Martial Arts by and large went extinct with the rise of gunpowder, or morphed into new forms, some focusing on marksmanship or interfacing with machinery, or into those with sporting concerns being first and foremost. This left the lethal melee combat arts of Europe neglected, forgotten, and then finally dismissed by Victorian fencing historians, from whom came the popular notion of medieval knights being nothing more than crude untutored fighters. Ironically, what was considered "historical fact" couldn't be farther from the truth.
It is to make sure that these arts aren't forgotten again is why I teach. The Masters of Defence wrote down their teachings for posterity, and now hundreds of years later, they have students from all over the world who study their writings diligently, and strive to put them into practice. In my own way, I try to be a fighter of whom the historical masters would not be ashamed. I'm not there yet, but maye in a decade or two.
There's also the cultural beef I have with the term "Martial Arts". The term was first used poetically to describe western rapier fencing, not Asian combat systems. Though of course the term can be applied to them as well, it is applied ONLY to them in much popular culture. That irritates me, to tell the truth.

Hopefully, I can do my part to rectify that situation.
And also, it's just fun to train with swords.

And it gets more fun every time I do it!
Best regards,
-Mark