Seperated not divorced but new gf is prego

I am not divorced but have been seperated for over a year now and just have to get it done. My current gf we just found out is prego. Should i keep this a secret from my ex wife? If she finds out could this be used against me when we do go forthwith the divorce. She wanted the divorce and she also had sex with another guy while we were married. Just to give you a little background.

Adultery is still a crime in NC, however as far as affecting your divorce it will not be an issue legally with respect to divorce and/or property distribution.