I will answer this question honestly and would appreciate no flaming, I've taken it enough on this board for being honest:
We became buddies, then best friends, then fell deeply, madly in love then, after months, cheated on our respective spouses (out of stupidity and fear and doubt if it was the "real thing") eventually left our spouses in unpleasant (emotionally and financially) divorces and have been blissfully happily together a total of 15 years.
However, we are the exception, not the norm. Most relationships borne of adultery crash and burn.
However, I will state that, IMHO, it is not possible to "lure" someone out of a good (happy, healthy) relationship. If you're truly in love with your s/o, you generally don't go looking for (or rather, will not see) love elsewhere (500 mg test. e/w not withstanding).