geisha, when you say you are nice (which is great), could you be too nice? Dh and I are on our second aupair. I would say that we treat her like a member of the family, but not a guest. So she is expected to muck in eg she takes turn to wash up dishes, tidy up the house and entertain the children, even if it is outside her strict work hours, so long as she is in the house.
I make this clear in the houserules. In my mind, I am not her skivvy (nor is she mine).
Of course, this does not happen when she is out of the house, which gives her an incentive to get out every now and then.
And whilst we ask her about her day, weekend and let her know our plans, we don't make a particular effort on a day-to-day basis to make conversation with her. If she is having dinner with us or chooses to stay around the living room with us in the evenings, dh and I have our catch-ups without necessarily including her. She is free to listen and pipe up, but it is quite an easy and casual relationship. As a result, we don't really notice or mind if she is there. It is up to her. I also prefer to maintain a slight professional reserve whilst being friendly (ie I don't overly confide in her or encourage vice versa on the basis we respect her privacy as well), as ever so often, I will have to tell her she did not clean the sink thoroughly or she missed that out and show her how to do things.
Yes, once she has friends, she will prefer to go out anyway . We make ourselves slightly boring.