Teresa, if you haven't yet, read Ann's recent post In Between -- I think it is where we mothers reside often, as you said, "wanting to "rescue" and wanting to kick his ASS!" That is another kind of "in between" than the article refers to, I know, but it is kind of funny in a healthy way: "I am glad you are alive, son, but now I am going to...."
That kind of rage gave me fuel to keep my boundaries during my daughter's summertime relapse escapades.
My therapist reminded me that mothers have a documented biological connection to their children, something in our very cells, that makes this kind of repeat trauma especially painful. Take it easy on yourself today. You don't have to open your heart today, or tomorrow, if that means putting yourself at risk with him again. Love him from a distance. It's okay, and doesn't mean you aren't a good or loving mother...you just need a little bit of a stronger shield around you right now.