No matter how anyone else behaves, be honourable. Stay true to who God wants you to be - pure, full of love, blameless. Don't give in to the desire to return poor behaviours with negative ones of your own. It's so easy to do, but just creates a downward spiral. And God wants you to be "better than that". And in the end, it all comes down to who you are before God. No one else is included in that equation.