Re: How to handle this??
You are a wonderful father, and an amazingly forgiving, patient, loving spouse from the sound of everything. You are still in love with your ex-wife.
For your children, they don't care what went down, they just want mommy and daddy together. As parents we do anything we can to hold that home life together, and give them that haven we know they all deserve.
Then one parent shatters it. As the other parent, and as a spouse that has never known an adult life outside of loving this person, you think, "How do I move on?" It seems impossible. You selflessly extend reconciliation. In your case, multiple times. She knows that you are so in love with her. That you want to turn back time and have back the family that was. Yet, she has been given second and third chances, and probably even hundredth and two hundredth chances as far as you listening to the "I'm coming home this weekend" statements. Her words mean so much to you, yet she has showed your for so long that your wants and needs have no importance to her whatsoever. How brutal.
I agree that you really do need to stop any communicating with her other than strictly to do with the kids, and at that, very minimally. I'm afraid you aren't willing to do that yet. Maybe you won't ever be?
I think it is unfair to romantically bring in another innocent party, if you are still in love with your wife. Yet, I think you may need to date and fall for someone else to finally get over your wife. How can you have both? I guess you have to be very honest (like you have been with second date lady) and go slow and have full disclosure with anyone. I agree with other posters that there are not many women who would be willing to date a man who is still in love with their ex. It's all easy for everyone on an Internet forum to tell you how to feel and what to think and do. Real feelings and emotions are rarely that cut and dry for most of us. Even if we know what we should do on an intellectual level, our hearts are a whole different matter.
I hope that you can find the right balance so that you can move on with your life, and have a partner that is as loyal as you are. You deserve that, and the time is overdue for it to happen.