Americans are suckers for a redemption story. You make a mistake, go to rehab, and come back reformed. A clearly defined arc. But if we've learned anything from our favorite television dramas, men like Tony Soprano make the same mistakes time after time.
If someone wants to engage in an affair, or leave you for an affair partner, no amount of rational argument is going to sway them otherwise. Don't hector, beg, or argue. Just remove yourself from the equation.
The sensible part of me would break things off with Mr. Married. My reasons are twofold: I don't want to make myself emotionally available to someone who's not available to me, and I don't want to be a party to a secret with this kind of potential for harm.
Great relationships require a high level of integrity in order to thrive. When a violation of trust, large or small, occurs, it's important to examine the conditions that contributed to the situation and to engage in a healing process that will restore trust and goodwill to the relationship.
The ability to marry now means that many couples who have had to forge their own definition of a committed relationship will now have a ready-to-adopt model that according to some pundits, has been in place since Adam and Eve.