I'm so glad to hear that you had one entirely pleasant day! I really do believe your W is slowly working her way back to you...sure she could turn around and be a shrew tomorrow, but your interactions with her for this one day were all positive!!! That had to feel good!! There's more of this to come.
Also, when you get a chance would you pop in on Help-Needed's thread? She's pretty much where you were at when you first started posting...she has an H who is trying desperately to push her away (like your W)...as far as I know no OW involved, but other than that similar circumstances. She really needs someone who is currently going through something similar to give her their perspective and support.