When you and your partner style yourselves Mom and Dad, you assume a loaded kind of authority which can easily become incestuous. So if you truly desire parental responsibility, have or adopt children of your own and raise them to maturity. Meanwhile avoid using your coven as a surrogate for the 'perfect' nuclear family you never had. In my experience, teachers who get sexually involved with their students are asking for trouble. This may sound harsh, but in the long run it's the best policy.
Most women recognize that sleeping with the boss is a sleazy thing to do.
Some Neo-Pagan groups advocate polygamous lifestyles, and that is certainly their right. Yet in my experience a coven that both prays and lays together doesn't stay together too long. Life might be different if the female of our species were not genetically designed to pair-bond through intercourse. I can only assume the Goddess made most of us this way for good and sufficient reasons. At any rate, the longterm soap opera quotient in every multiple and overlapping relationship I've observed has convinced me that the game is unworthy of the candle.