I think it depends on the age of the child, how mature they are, and how serious the relationship is. Age plays an obvious part in it, a 5 year old would have a different understanding then a 13 year old and yet the 5 year old may be more accepting of it where as a 13 year old may harbor stronger feelings. I think that a relationship has to be headed towards something permanent, not just those first months where everything feels right, we know how quickly things can change. Since she already knows this man it may make it easier, I would keep the grown up part to yourselves, but set up times where you can do thing togather, but revolve around things your child likes to do, and gradually introduce your relationship....I know what I am trying to say but am having a hard time finding the words, is what I am saying make any sence? Good luck!