I have two daughters aged 21 months and 3 and a half. I've had a 19 year old live-in nanny working with me for 5 months. Most of the time she works alongside me as I don't work, but her contract stipulates that she works one weekend in three and I sometimes go away over those weekends so she's in sole charge of the children. Last weekend I was away and in the previous week, she asked whether her boyfriend could come and stay with her for the weekend. She asked in a way that made it quite hard for me to say no, and initially I agreed. However, after some time thinking about it, I realised that it actually made me feel really uncomfortable especially since he's a fairly new boyfriend to her and I've never met him. I therefore apologised for changing my mind and explained to her that I didn't want her boyfriend coming to the house as I hadn't met him and I felt it was inappropriate whilst she was being paid to look after my children. She was a bit uppity with me but did agree. When I returned on Sunday evening, there were a couple of signs that someone had stayed with her over the weekend. My friend's daughter has keys for my house and let's herself in at weekends to walk my dog. When I mentioned my concerns to her, she said that her daughter had had a problem opening my front door and that she had been helped by a man who was in my house. This was at around 4pm on Saturday. I can only assume that this was my nanny's boyfriend. Can anyone give me any advice as to whether this would be considered "gross misconduct"?