Honestly, and this is probably just the cynic in me, I think it's far more likely she's recanting because there's money with her name on it if Foster is cleared than anything else.
Victims of DV do this type of stuff - even when there isn't massive financial gain to be had like in this situation. They go back on what they said, they say it's their own fault for things escalating, they say things didn't actually happen the way they initially explained it, they say that they somehow already had their injuries, etc. They stop working with the prosecutors and then the next thing we know the perp. gets a slap on the wrist.
Even if this all blows over, I would never trust Foster moving forward. I'm not rooting for his demise, but I would be surprised if he straightened up and didn't have trouble continue to follow him.