I am in the same boat too...I have the same type of husband...I never would have thought he could have treated me this way. He's been having his A now for 3 months...I found out after 6 weeks. I have been fairly successful at appying the DB principles...but it is easier for me because my H travels extensively for work (and to where the OW lives). I only have to cope with him for 1-2 days a week.
I agree with the other posters though...try to focus on yourself as much as you can, enjoy your kids, buy yourself some new clothes/underwear/etc (justify it by realizing he is probably spending $$ on his A), and do some unexpected things. I found my H reacted well when I went out for drinks with a friend when I could have been clingy and done things with him and the kids.
This is miserable and I'm sure I won't do this for very long...but, I feel like an ultimatum right now isn't really what I want. Plus, the timing is so hard right now with the holidays coming up.
Hang in there and know you are not alone!
M 44, H 46 D11, D9, D5 Married 12 years PA confirmed 9/2011 I filed 3/2012 H moved out 7/2012