I don't care for John or amy very much, although your side characters seem pretty strong.
Personally I don't care for battered woman and weak man couples. They are very over done lifetime murdered and raped it and keeps it in a dungeon.
However, it's still early in the story and I see the story going a few ways.
1. Nate saves her, like in most movies.
2. She grows over time and through development gets stronger then him and leaves.
3. Chelsea tells Amy she is being abused as well and together they work out the problems.(girl power)
4.John turns into a killer and Amy kills him.
Those are the most commonly used routes in this kind of story and you should avoid using this.
Try too be innovative and it will be fine.
From what I noticed on my cell phone a few I's were placed as "i" and a few words were mispelled. Also some of the info in gym class part seemed unnecessary. However it isn't awful, the story is very easy to follow which is always good as a the story flows very well from one
part to the next.