So basically my wife went off the wall and beat me in the head a while back.  

Now she's alternately conciliatory and abusive.  To much greater extremes than before.

She is supposedly going to begin treatment for BPD, but I am unsure how serious she really is.

In a situation like this, what can I do to keep things cool when she so frequently becomes abusive (verbally, emotionally)?  We have a daughter together that is 2 so we are somewhat forced into contact with each other. 