I think a lot of it depends on the type of cybe communication there is.
It's human nature to want to communicate with other people, be it male or female. It's how we thrive.
BUT...if it's something more than just writing back and forth, I'd go as far as even then saying a little curiosity is somewhat normal, and it can feel restraining I guess, if you can't have that healthy (HEALTHY
But there should be a boundary somewhere that tells a person, hey this is making me feel differently towards my wife/husband and at that point you'd hope that the person or persons would re-evalute why.
If it's something your partner is doing and just can't stop, well no amount of force is going to make it any more balanced/natural in their not wanting to do it anymore.
If that's the case, my opinion/feeling is - establish your own network and explore that avenue...so turn a negative into a positive