Yeah, this situation sucks. I really wish you would see your family therapist before you make more suggestions about how exactly to implement NC though.
Here's my thinking. So TKD is important to her. Fine. Is her marriage important to her? So what was she thinking when she initiated an affair at her TKD classes?
We make choices in life. Our choices have consequences.
There's an old platitude about romances in the workplace that could be updated for this situation:
Don't crap where you eat.
In this case it's "Don't crap where you play if playing there is so gosh darned important to you".
As Starsky has pointed out to you, any contact at all (even negative contact) is likely to set you back to square 1 where she just has no loving feelings for you.
So... that's the risk to you, your family and your marriage. How long can you and your family endure being on this rollercoaster before you finally snap, and you become the one who is leaving and who has no interest whatsoever in rekindling things.
That might sound crazy to you right now, but we have seen that happen over and over and over, so it's not as crazy as it might sound.
M-47,W-40,No kids D-filed 5/27/2010 Piecing - 10/21/2010 -=Soon to be banned=-