Had done two readings about relationship in a row recently, found out that when someone is intentionally breaking into someones relationship, many suffered... Of course mainly the wife or the husband, and the children!
But when we come to think about it in a long run, all suffer. It won't be easy cheating on your wife or your husband and children, as well as being the ''someone'' forcing a beautiful marriage or a beautiful family to break apart.

Why? Is this a normal thing that every couple would face in their lives? Is a marriage tied up with leash or without? Have we forgotten the promises and the commitments after some time?
If one always does things properly, remember their responsibilities, learn to love the people around them well, appreciate things done by others, I guess the chances of having or the desire of wanting to enjoy an affair outside will be lesser.
''Everything that you have is very, very short-term. And the most important thing that you have in your lives are the people that care about you, that have stuck through with you loyally and that have been by your side, with all your bad habits, all your bad tempers, all your bad words, and all your bad anger. In spite of all that, it's the people that stuck by, short or long term. And, in the end, we can lose everything except those people."
~Tsem Tulku Rinpoche, Bring Dharma Home.