I perfectly understand what you are going through. I went through the same thing 8 years ago. I hear myself in all the questions you are asking yourself accompanied by all the emotional turmoil. Having a spouse leave is very confronting. It hits right at the core of all we are. It puts our very self into question. We wonder how will put ourself back together with the life we were trying to build, and the dreams we hoped would come true.
There were three things that helped me. It is a life long journey.
Firstly, I knew that God loved me. Once I got through asking all the why questions, I really needed to know How I was going to get through.
Secondly, the Book of Mormon provided peace, comfort, revelation in ways I could have never imagined. It is the best source of LIGHT for any circumstance.
Thirdly, I read about others who had grieved, and felt comforted in the fact that I was now having to grow up, and experience some adult events, that would teach me.
C.S. Lewis' works are marvellous. "A grief observed", and "Mere Christianity" are an eye-opener.
Practically speaking, you need to let your wife live her own journey. She may come back, she may not. It is really important that your grief does not turn to desperation that makes you behave in ways that will permanently alienate her.
I know that for marriage to work, each partner needs to be themself without manipulation, compulsion, control, expectation etc. From the book "The Prophet", you need to be a column and your wife a column, holding up the same roof, but not being the same column. You are independent, free-thinking people with your own feelings etc, and that needs to be respected.
I am not the same person today as I was before my spouse left. I have very deep scars which in time the Lord will heal. That I know.
I spent 4 years hoping that my spouse would see the light and come home, but that was a separate journey.
Find your own sense of joy and purpose (that is very difficult, because love for a spouse can seem like our only purpose, and only source of joy). When you learn to lose your dependence on your wife, she will see the difference, and it will free her. You must not see your relationship as one of ownership. Stand on your own two feet, that will be your journey, and everything else will be your own personal tale to tell.
