Wife Wants Older Man

When my wife and I have sex we often fantasise about who we would like to fuck or what risky place we would like to do it. It’s often things like me and her sister her being gang banged by my mates, fucking a a neighbour and having sex in a shop changing room pub toilets on the beach etc . Recently however she’s been saying she wants to be fucked by an old man with a heavy thick dong. She remembers seeing a guy on holiday when she was young and it was on a beach and he stripped and changed in front of everyone . His dick was extremely thick and heavy and she couldn’t take her eyes off it. Now she keeps asking me to look on line and set up a hotel session with an old man. Our fantasies are great but I’m not sure I should actually let her be shagged by a wrinkly with a huge cock.
Has any other readers experienced this and should I let her go through with it. Im worried if I don’t she might do it behind my back. Maybe she already has someone in mind that she knows.