Man, I have tears in my eyes. Congratulations to you. From a woman's perspective, or at least from my own, how your wife is beginning to respond to you is HUGE.
Quote: She's acting like she knows that I'm on her side finally.
That's exactly what this is all about. Her opening up verbally to you means she is beginning to let down her guard. And yes, you are correct when you say you feel like you are on a second date...you are dating your wife again. Just be careful not to rush it. Though the physical signs you've noticed seem subtle to you, they may not be all that subtle for her. They may in fact be very huge for her.
Are you hanging in there okay? Do you mind dating your wife? How does it feel for you, as a man, to see yourself as you are now through her eyes? What does this new trust she is finding in you feel like? How does it feel to you when she opens up to you about her day, about her feelings, etc., that she used to not share with you?