A married man and a married woman are drawn to each other. That can be a very strengthening and stabilizing experience. Unless, of course, they happen not to be married to each other. Then the effect can be quite the opposite—weakening and destabilizing. Not just for the two individuals but for their families and for society itself.
The fact that people sometimes find themselves in such a situation isn't a product of the way modern life has evolved. It's an age-old event. And the solution is age-old too. It could be described in a word: chastity. This may not be seen as a very fashionable answer in today's world. Nevertheless it is an answer that has worked for centuries.
On the surface, chastity may be thought of in relation to an unmarried person refraining from sex, or a married couple remaining faithful to each other. Such conduct certainly can be a powerful force for stability in society. But if it rests just on the best human effort we can make to do the right thing, that steadying influence may not always hold.