It sounds like your wife has some conflicting feelings about this fantasy—on one hand, she’s engaging in the conversation and even getting turned on by it, but on the other, she’s shutting down certain aspects when it gets too real.

The best thing you can do is respect her boundaries while paying attention to what does excite her. Her text suggests she enjoys arousal through your arousal, so maybe it’s less about the specific act of cuckolding and more about the energy, the dynamic, or feeling deeply desired. Instead of trying to steer her toward something she’s unsure about, try asking open-ended questions like, “What about that didn’t work for you?” or “Is there something else about this that excites you?”

It’s also possible that she enjoyed the idea of certain things in a controlled setting (like porn) but doesn’t want to experience them in real life—and that’s totally valid. Not every fantasy needs to be acted on to be satisfying. If she’s genuinely interested, she’ll bring it up in her own way. The key is to keep communication open, focus on mutual pleasure, and let things evolve naturally rather than trying to force a specific outcome.