I've never had an au pair, or anyone else working in my house. Im not sure i would like it if i am honest, DP and I are pretty anti social, so your OP sounds just about perfect to me! But, at the end of the day, she is looking after your children, how much time is she spending with them? I guess by their age they don't need the sort of input a pre-schooler would? Im just thinking that, you know, this is your home and whilst, technically she isn't doing anything wrong, maybe you should set a time limit and if you still don't feel comfortable with her, then find someone else.
I actually think the "forgein help" is quite good for the children, she can tell them all about her country etc so there is potentially a real benefit there. I don't think your children will throw it back in your face at all - why would they.
I am a SAHM, my DD has just started preschool, and I worry for the opposite reason, we are broke, im looking for a job now.
Its such a personal thing having other people in your house, i couldn't take to it i don't think. But that is cos im weird .
I dont think you are being unreasonable, it might be that your AP doesn't feel comfortable with you too, that sounds harsh, but well, people either gel or they don't. I don't think that means anyone person is in the wrong. I would have a problem with her walking into a room and not speaking, unless of course i felt VERY comfortable, but this isn't the case.