Dossie Easton and Janet W. Hardy are the authors of “The Ethical Slut: A Practical Guide to Polyamory, Open Relationships & Other Adventures.”

Open marriages can work, and have worked for thousands of couples over decades if not centuries. However, there’s much more involved in maintaining an open marriage than simply asking for one. Such relationships require an ongoing commitment to communication and mutual support, and will almost certainly involve some journeying in the vulnerable territories of jealousy, insecurity and anger – but what marriage does not?

Much pain could be avoided if couples discussed monogamy as an option during the dating phase of their relationship, rather than assuming it as a default.

Opening a previously monogamous relationship is customarily negotiated before the openness occurs. Polyamorists consider it bad form to introduce one’s spouse to one’s secret lover with a cheery, "Honey, I've been thinking we should open our relationship!" Given that a major deceit has already taken place, many, perhaps most, marriages will not survive such a revelation. The path back from that situation to a healthy open relationship is a steep and painful one – yet many couples do survive it, and achieve more satisfaction, growth and closeness for having done so.

The ethics of any sexual behavior depends on the values and customs of the community and culture around it. People who are generally open-minded about sex and who are aware of polyamory as an option will have an easier time than those who believe that the desire for an open relationship must mean that their spouse no longer loves them.

Much pain could be avoided if couples discussed monogamy as an option during the dating phase of their relationship, rather than assuming it as a default – just like the choice to have kids or not, the choice to have one career or two, and any other important decisions that must be made before proceeding with a long-term commitment. As we say in “The Ethical Slut,” monogamy is not “much of a choice when you are forbidden to choose anything else.”