I work in dementia nursing and I've found a number of set phrases will help in reducing sexual inappropriateness, spoken in a sort of theatrical, earthy way:

Easy Tiger.

I'm a married woman.

My husband is the jealous type.

He's a black belt in karate.

I've got a reputation to protect.

I can't have people thinking I'm some sort of scarlet woman.

(I'm actually male if you haven't guessed, but often patients get confused. Sometimes I use those phrases in the third person if one of my female colleagues or a visitor is being poked at. These phrases are framed in a sort of old-fashioned way because that will make sense to them more than describing the modern rules. Of course, while this may work to stop inappropriateness it must feel very different when it's a relat