I can best offer you my hopes that everything works out. My best thought on your situation is that you have a good start on what to say already! You said some things about how you feel, now expand on all of that in a looooooooooooooooooooooooong letter to your inlaws. Don't worry if it ends up being 3 or 4 pages. I think that as long as it comes from the heart is what matters here. Be honest and respectful. When I do something like this, I always edit and re-edit and edit some more. Perhaps it's overkill on my part, but like you I will want it to say exactly what I feel. I don't think it's possible to put our emotions on to paper, to make another understand so perfectly how we feel. Whatever you write may never be just the right words, but don't underestimate yourself. I believe from reading your post that you already have what it takes to pick up that pen--you just haven't realized it yet.

Hope this helps!!!