I don't think that Adam did anything but he thinks that he did. In the case of nut case, Sharon, she is lying through her nasty teeth to Nick and he should never forgive her or cover for her, for what she has done. She has ruined so many people's lives by what she did and as she tries to profess loving Nick, she has betrayed him in the worst way any woman could betray a man. She has cuckholded him with his own brother and now she has stolen his child away from him for her own selfish needs. The woman is a creepy trick who needs to have her butt kicked to the moon. If anything, Nick needs to kick her off his ranch and take Faith from her and then go find out if Faith is really his child because frankly, I don't think that she is.
If Nick tries to cover for what this dirty little nasty trick did, then he will look like the weakest most ignorant idiot that ever existed. He already looks like a fool, just wasting his time with that no good, common, low down piece of pond scum, and then to cover for her and what she did? He would be nothing but a weakling little snit who can't face his own reality either. This, people will never forgive him for. It would be like compounding his mistake and just piling on more. Nikki and Victor can't stand that trick and I am sure Jack will definately not forgive her when he finds out why Phyllis is really in that coma. Summer isn't going to forgive Sharon and if Nick covers for her sorry butt, he better not expect Summer to come aroun him either.
Basically, Nick will alienate his entire world if he tries to cover for that trick this time. She ain't worth that to him.