Would you expect to be friends? Are you not her LL?
I think giving over part of your home to a paying tenant is incredibly difficult, especially if you are used to having it to yourself.
I think one of the hardest parts is to realise that, while you have expectations of your tenant (and these expectations should be very clear and included in the tenancy agreement), your tenant will have equally strong expectations of you as their landlord.
For example, unless having guests was specifically excluded in the tenancy agreement, I think you are being unreasonable to expect her to ask your permission to invite guests (though possibly courteous to mention that she is expecting someone).
Certainly this is your home and you have a right to enjoy your use of it, however she is renting her home from you, it is within your home, and she has a a right to enjoy her use of it.
It is difficult. If you want to give her notice, then you should do so. If you decide to have a lodger in the future, perhaps you should have a good old think about your requirements, make them very clear from the outset and incorporate them in the tenancy agreement.