Don't you just love the no b.s. incites Warbaby brings to these discussions?
As someone who has been in the scene for many years, and who has been married to someone who I love more every day, it really has become a balancing act. My wife knew of my lifestyle when she married me, and she agreed that she would not object to me playing with another sub, as long as she knew about it. No sneaking around! That means in r/l or on the internet.
Like Warbaby said, even if it is on-line, a relationship is still real. The internet allows us to have a relationship with someone on another continent, but it's all really a mind game. Since the mind is the most devious of sex organs, it allows us to do just about anything.
But we must be careful. A breakup can be devastating as SBBE has stated. With that in mind, yes I like to role play as evidenced by the two I'm involved with now. However, I am not going to risk my marriage by getting involved in a serious D/s relationship with anyone, either in r/l or in cyber.