I live in Forsyth County and I served my ex via certified mail and his girlfriend signed for them. Does that still count or do I need to resend them?
If the girlfriend lives with him it is sufficient to have her sign for the certified mail receipt. A party of suitable age and discretion that lives at the same address can accept service. Your ex could later raise a defense of insufficient service of process - if you are worried that he may do this you could have him served again at work or at home.