h4h, I know what you feel when you talk about B, but like everybody says, be careful. You and W still live under the same roof. W is making a mistake, and usually you don't fix a mistake with another mistake...., anyway, maybe you can show W that there is somebody there ready to get you, but you have to play it well, it shouldn't be a threat, just so W starts thinking she is not the one with the handle of the sword.
When I asked my pediatrician about how D can affect the kids he told me that often kids around age 5-10 start to wet beds. Some say it may just be the stress, other say is a form of regression to a happier age, when the parents where together. The solution is not to make a big deal out of it, tell her it is ok, it happens, it happened to you too at her age.