Hrm...
having a wife who is sub.. I would not interfer if she wanted a online master. As long as things were understood ahead.
jealousy perhaps.... but it's two way.. she could be jealous of wlg or some of the others i talk with and some i play with online.

I think it's not a question of one submitting to one or more than one.
It's a matter of internal relationship handling..
It's not for everyone. And each handles it differently if at all.

I agree with Rhabbi that ToS may handle his own, but he speaks of many slaves, but not of thier jealousy.
Theirs is the one to be concerned with or not.
That is how i view being involved with many through out the day.