Welcome to SR Hulk!
You both have skewed perceptions of the situation - she blame shifts everything to you, and you see that her life "has no obstacles....all roads have been cleared". Not true my friend, its just not the way it is.
Your wife is making some really detrimental decisions and you are correct, she is acting like she just left her parents house to head to college with no responsibilities and only the world to conquer. Even 20 year olds get a dose of that reality, really quick. The world is not a soft bed to land on - its tough, really tough.
Its much harder when you are an addict as well.
I can't say how long it will take you to get over the betrayal. What I can tell you is you will. When the loneliness abates (and it will) you will see glimmers of life without chaos, life without a drunk disturbing the peace, life without lies and manipulation, life without anger and sadness mixed together.
it may feel like nothing has been your choice for 15 years, that is also not true. It has all been your choice in as far as what YOU have done in dealing with your wife. You chose to stay, you chose to support, you chose to continue. If you can get a good grasp on that it will help you as feeling like you are a pinball being knocked around with no power is a terrible way to feel.
I recommend you get to Al Anon as soon as you can. Al Anon is to help you, focus on you, and it teaches you how to control your life while entangled with an A.
I'd like to say that the wheels set in motion by your wife will continue their path, but history shows that most likely she will try to return to you. I can't say that for sure. Alcoholics need enablers and co-dependents. Your wife, as you describe, has not had to have much if any responsibility over many years. That's a whopper transition. The best you can do for you and your kids is switch the focus off the alcoholic that is caused so much misery, and focus on your family and doing what is best for them. Not what's best for her.
((((hugs)))). You can and will get through this.