Then if the baby does turn out to be his, tell her. If not, then its not something she needs to know.
I'm not sure waiting to tell her is going to lessen the shock, just MHO, I'm sure you've talked about it with her C.
Also, not sure why it wouldn't be something to tell her even if it's not his. I understand wanting to protect her, but kids are pretty intuitive and I'm sure she knows things are going on regardless of what she's been told. I think she'll hear things and figure it all out at some point regardless of whether the baby is his or not.
Michelle - Proud DR Rockette S: 28JUL07, D'd: 29OCT09 http://tinyurl.com/27j9qo2