Dear lost in love,
First let me congratulate you for your devotion to your marriage. That is becoming a rare thing to find in this day and age.
Your letter is a little confusing to me because the picture that you paint seems so rosy. If this is a true representation of your view of your marriage, it is no wonder that her pronouncement has come as a surprise to you.
Unhappiness Is Not Grounds For Divorce
The most important decision to be made here is whether or not to seek divorce. It sounds to me like you have your values in place on this issue. Marriage is "'Till death do us part." I know of only two good grounds for divorce and just being unhappy isn't one of them. That said, you do not have to stay unhappy.
Read About Dwindling Love
I would recommend that you read a book called, THE FIVE LOVE LANGUAGES. The book addresses the issue of dwindling love.
You do not mention how old Angeline was when you got married but you do say that she was young. She may be operating under a very common misperception that the thrill and excitement of the early stages of dating will last forever. Unfortunately this isn't so.
While you do need to remain married, you do not need to just sit and wait for her decision. Be proactive.
Clearly, you love her. Just as clearly, she isn't feeling it.
Learn To Show Your Love
That is why you need to read this book and learn how to show your love in a love language that she will understand. I don't think that she is just looking for an excuse for a divorce. If so, she would have done it long ago.
But she has been languishing for 6 years now in what may feel to her as a loveless marriage.
Buy a copy of the book. Read it together if she is willing. If she won't, you can put the principles into action yourself. It doesn't sound as if you have much to lose but a marriage to gain.