Adulterous women were condemned because of the affect that has on children, and society in general. If mommy is promiscuous, how does the kid know who their daddy really is? Not good. In the case of running off into the woods together, in that culture--people don't really date. They court. There are careful, cautious customs about gender relations. So if a couple runs off into the woods together--hmmmm... yeah, pretty much they're probably up to no good. Her returning and accusing him of rape means she's demanding his death.