OK - Vows, promises and agreements between life-partners (for want of a better neutral word) that are being adhered to must be binding, and deliberately stepping outside the limits breaks the commitiments given and received. That's cheating.

But eventually, sometimes, those undertakings lapse or are neglected, or just become irrelevant. Nevertheless, the relationship continues, either because it is comfortable, or because it remains a loving relationship notwithstanding its shortcomings. Life changes things over time and relationships alter in response. What was important once might not be now. If one then goes beyond the old agreed limits, is it still cheating? Or if so, does it matter?

You might say, it's only OK if the other partner consents. I say, if it is necessary to obtain permission then it is still important to the relationship (in which case the original undertakings apply). Just because something isn't quite working for one person in a relationship doesn't mean he/she has to highlight it to the other if it can be discretely dealt with separately. To my mind, that would elevate a minor problem to a major issue that could eventually ruin the partnership entirely.

(Sometimes a partnership is forced to continue for economic/family/other reasons or because one partner simply refuses to accept the reality that the relationship has broken down. That is a different situation from what I have described above. And to my mind, there can be no cheating because the undertakings evaporated when the partnership hit the rocks and the "wayward" partner has no duty of fidelity towards the other.)

Isabelle also asks how the couple who are "playing away" can possibly trust each other knowing that they are cheating on at least one other person. Assuming it is cheating, they can't. But I guess they take a calculated risk that it will work for them as far as they want it to. After all, apart from spotty, spunk-filled teenagers bent on destroying Casanova's claim to be the world's best lover, most people want to have an honest relationship with their lover. If there's no trust, then I do not see how the relationship can progress beyond crude sex.

TYWD