BFP#1 - 11/27/09 EDD 8/5/10, DS1 arrived 7/24/10 via emergency c-section.
BFP#2 - 6/18/12 EDD 2/23/13, sweet baby girl born sleeping on 10/4/12 at 19 weeks, 3 days.
BFP #3 - 1/18/13 EDD 10/1/13, natural mc on 2/2/13 at 5 weeks, 4 days.
BFP #4 - 8/29/13 EDD 5/12/14, our sweet rainbow, DS2 born 4/29/14 via c-section
Re: Biting nails
It is self soothing behavior. DS recently started toying with his belly button as his self soothing behavior. It is driving me NUTS.
I do redirect. Once in a while I will ask him to leave his belly button alone but mostly, I find it more comfortable for him if I give him something else to do.
Since he's not witnessing nail biting in your home, I am inclined to think that this too shall pass.