You should never hide anything from your partner. True it takes time to build trust in a relationship but after awhile your partner should know everything about you. Coming on line and chatting about sexual things with other people shouldnt be an issue of weither to be open or sneak around tring to not get caught. The answer is DONT DO IT. If you need to go to other people to fulfill a desire that your partner isnt willing to fulfil with you but yet you havent even asked is a major communication problem. If you have asked and they flat out say they wont be apart of it either except that and keep it as a fantasy or openly ask how they would feel if you found someone who would wither its a one time deal or more. I think even in a Dom/sub relationship there has to be open communication; even if it is set up that the Dom has finally say. Without communication and trust there is no reason to allow the relationship to continue. And sneaking around behind your partners back is a lack of both.