Let me be the first to welcome you to our community here at DB. You will get lots of support here if you'll post often and keep us updated about your stitch.
I hope you'll read Divorce Remedy.
Even though the stories here begin to sound a lot alike, they still are individual and yours is that very example. My heart felt heavy reading about your young bride and the horrible things she suffered at the hands of her biological parents. It sounds, however, that she has a good relationships with her foster parents. How does she feel about her foster father?
I'm sure you've been told that the first year of M can be tough. Couples can say things out of their own insecurities, and they don't even mean it, but it's the wrong thing to say. I think that's what happened in your case.
Your W has good reason to not have very high opinion of men. She was forever scared by the one who should have been her protector. Must be awful hard to establish trust. That's one reason I asked about her foster dad and how she felt toward him.
This could take some time for her to feel she could trust you not to hurt her emotionally. She may build a wall around herself trying to keep you out. The foster parents my be your only link to her, so I hope you can stay on good terms there. They must like you if they are willing to talk to you and keep you updated.
For now, finish your books and make some personal goals. Did she ever complain about any particular fault in you? If it's something you can change and improve, then start working on it and mold that into a positive pattern.
Give her some time without you near her. It will be difficult, but try your best not to press her. I know you must fear losing her, but she has to make the decision to trust you again. Hopefully, you will be able to have another shot at a life-long R with her. The one thing you never do is threaten. She needs to believe you aren't going anywhere and you are trustworthy for her heart.
You won't find that advice too much here on the board, b/c in most cases the LBH is dealing with a WAW who is involved in an A. In those circumstances, things would need to be handled, IMHO, a bit differently than yours.
Have you been back to see the MC since she left?
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!