I mean, you reap what you sow, I'm not saying that is OK to ostracize or making "a desprestige campaign" towards someone, is not OK no matter who shitty the person is, but she can't either have the cake and eat it, you can't just pretend that nobody should care about anything, that she goes sleeping with half town and maybe in that half-town is your partner, and you chose to be indifferent or not care just because it wasn't with you, everything comes and bit you on the ass sooner or later, and if she have been that way all her life and haven reflected on anything says a lot about her.
I neither pitty her, or try to even rationalize her, or try to say that what's happening her she deserves it, is just that no matter how many sides an story has, there are some things rights and wrong, and some actions could be avoided or done differently.