@PokGai,
You two need counseling. Yesterday.
Not just to see if you can save your marriage. It's possible that you won't be able to, and it is further possible that that would not be the best thing for you to do. But that's not my call; it's yours.
Why do I say that you might be better off apart? Because you are currently going through the motions, and it's awful. Can you change? Maybe. But you have had several allowances and chances and you have not. Hearing that this time, you really, really mean it, well, if I were her, I'd be kinda skeptical, too.
Furthermore, staying together is a very bad idea if you are not really in a marriage. It is not good for your children. No. Divorce is better. Why? Because by staying together, you are teaching them that love does not matter, and that all that matters is putting up a facade and lying to your kids.
Pretending to be happy is not better than being happy.
Should you try? Yes. I think parents in particular should. I do not discount the fact that divorce is a difficult thing. But the whole business of staying together for the sake of the kids is inertia at its finest. It is a means of justifying doing nothing. It feels safe, but what it really is, is a way to head off better opportunities at the pass.
If you met a woman you were better suited to tomorrow, you would be holding back and unable to be with her. Same goes for your wife.
Either go all in, or end it.
But try to fix it first, and that means going to a professional. Make a pact that you will try for a specific period of time (say, a year from when you start counseling), and then revisit. If counseling isn't helping, if you are just going through the motions, if you are miserable, then for God's sake, set each other free and give each other the opportunity to be happy as a final act of love for someone who at one time was very dear to you. For someone who, because you are parents together, will never truly be out of your life.
That is a better gift for them, and it is a far better example for your kids.