I think there is a shame on staying, on here.
But it's because in most - almost all - of the threads I read on here, the cheating partner (man, usually, as this is MN) has done fuck all to make it right.
The woman posts that "we're working on it" - we? Ha!
I suppose if your partner is genuinely remorseful and activity trying to fix it, you're less likely to post.
I have seen some posts say they're staying, and who else has managed it? And those threads seem to be supportive.
But mostly, the women posting are just posting that their partner is still lying, won't talk to them, tells them to get over it, etc etc. Or like one poster on here, whose husband was working so hard to save their marriage that he didn't bother buying her a Xmas present 
There's no shame in staying after cheating, but it's a crying shame when people stay when the cheater really REALLY doesn't deserve it.