There are marriages and there are marriages. You can expect/demand the sun, moon and the stars or almost nothing. It's a question of personality and perspective. But there is no doubt that the most important thing in a marriage, as in any other relationship, is honesty and real understanding.
In a marriage of the kind we all yearn to have, fidelity is vital. It implies a commitment that's total and complete. You seek the closest intimacy possible from no one else, so sufficient is the love you receive. What could be more reassuring, more meaningful? But a relationship that intense, comes with a price tag.
And infidelity in a relationship based on such love can be shattering. Nothing can fix that first fine careless rupture. Trust is ruptured forever. It's a betrayal that leaves you feeling painfully inadequate.
You look back through the prism of time and realise how wonderfully didactic you were in your youth! At 25, black and white could never co-exist. But then, life happens. And you realise that grey exists, and it is often a zone that needs far more maturity and understanding to inhabit than you ever dreamt.
When you've been married nearly 27 years, the first lesson you learn is that marriage is a relationship which, like human beings themselves, is constantly morphing and evolving. It's an equation where the variables change the answers constantly. People sometimes lead married lives together with infidelity between them. Children, autumn love, companionship allow such relationships to survive.
But at the end of the day, it's really what you want from your marriage and partner. You can survive infidelity (don't we survive everything?), but that's the right word, isn't it? Survive. If you want more, you have to sacrifice something. That my friend, is the nature of the beast.