I don't think Hillary gave any support or tacit approval. I think Bill was sleeping in the dog house for several years. I know some people assume that because she didn't divorce him that she must have approved but that's just bizarre and assuming that everyone will act the same way if rational. A married couple that have invested much of their life together will sometimes divorce after such an incident but sometimes they will genuinely reconcile, there is never one and only one way to resolve the problem.
Hillary in no way acted like those wives who stand meekly two steps behind their politician husband while admitting the affair in front of reporters. That's a strange crowd in itself, pay attention to those women's faces. Some appear to be just sticking it out with as passive a face as they can manage, others feel resigned to it, others have glares they just can't hide. But for some reason they're always up their with the bastard instead of staying home or watching the apology from a bar. It is sort of a strong Christian right sentiment too, that divorce is deeply frowned upon and the wife must always be subservient. Or it could just be that some want the bastard to get reelected before they ask for alimony.