I'm definitely with you NM - except W fights every day to justify an affair. You have a great opportunity in my opinion in that your W is "open" - if you believe she is being honest about just not finding feelings, then that is a huge opening.
I'm the opposite - my W crushed her feelings even though she had them! However, you wouldn't believe how many SAHMs have this happen. My W was the same for 7 years - everything she could ever want - but it didn't "fulfill" her. She used to love being a wife and mother, and I got her as much as I could.
If I had any advice, I would say just be fun and funny. Put a smile on your face even if you feel like your cheeks will crack. Think back to when you started dating, what she liked - but ONLY from a conversational standpoint. Think about what kind of stuff she likes to do, and ask about it.
You may already do all of this, but I'll repeat it again: Keep it light, conversational - but not mushy and romantic. Do NOT walk around moping. I have lost 30 pounds, got new clothes, a new haircut, and when W drops off my kids (we're separated) I fling open the door, and grin and hug them. We're only together at S6's basketball practice, but the whole time I focus on S6, and cheer him on, and laugh, and talk to people (I'm on last resort - so I don't talk to W) Also, D8 will come over and jump in my lap and hug and kiss me, and just talk like crazy. W NEVER sees me not smiling and laughing, and joking around.
In your situation, you can actually involve W with that. I did a spectacular job of that if I do say so myself, and it's the reason that W didn't divorce me immediately almost 2 years ago. We started with her hating my guts, and ended up being pretty good friends before she started her affair. If that hadn't happened, I believe we would be on the mend right now.
I have sort of rambled, but let me say this in closing: the MOST important thing you can do is let go. I couldn't do it. I look back, and I see times where I did let go a little, and W responded EVERY time.
Do it - it will feel like your heart is being ripped out through a sieve, but it'll work!
