i agree with susie100 , it is not like i do not trust my DH, but you know men are men, when they see a pretty face ( God forbid French, you know their language, soooo romantic, even freaking accent is!!) they start beahving totally different around a pretty girl.... I guess this is natural, if you have a handsome fit young guy around you in the house, you won;t be able to help it either: you WILL be acting different.
Thats why: I screen my au pairs very very thorouhgly. You may think I am nuts but I am not . In the last 8 years of my marriage I learnt few techniques as my husband works with females mostly, but luckily he is emploeys, so he (me) decides who works for him. I just can imnageine the hell you, MrsMople, are going thru! being heavily PG is not a joke .....
and I disagree with Missus84, quite a few teenage girls WILL be interested in 35 yo man. You obviously have never been in the same situation yourself
anyway, first rule: never ever hire an attarctive girl, but if you have, you cannot show your husband jellauos side of yours, he will just think you are nuts. So what I do I see what is it in her ( the girl's) behavior that attarcats him, sometimes it is very simple : her looking at him with puppy eyes, and I do the same for few days, usually thats enough, and he switches off from her to me, and then few days later everything is back to normal. The when I know that she does some things that he may not like , like personal charachteristics, I do drop it into conversation lightly without putting too much focus ion it, otherwise he ill suspects something is going on there and move off to dif subject quickly..... it always helps...... when I was younger , I also was a bit unsensitive around older married couples, no hunly punky, but still..... you never know untill you are yourself married, and with the child and the girl in question is half your and his age.....do not forget about midlife crisis too....
anyway try this and let me know how it goes. Ah, another thing: you have to be the one who pays her, she needs to know where is her bread buttered, and if you have had cleaners/au pairs before, when you talk to the gilr, do drop into the conversations once, that you had a "cleaner" who was too mcuh flirty and you had to drop her off But again it has to be done , like you are having a chit chat, like firends, not like you are threathening her, God forbid! some women they ignate form a challenge. I am sure your gilr is just swett and innocent one, but family is a priority and it is beter to be safe and sorry