I will let Alan take this one, as he is an absolute EXPERT on it. I felt the EXACT same way, but everything Alan said was dead on.
I won't say I am an expert, but I do READ experts on the subject... and most reccomend treating infidelity like an addiction... or insist that it IS an addiction much like gambling or hoarding... unhealthy, seductive, and selfish... destroys the whole family
Maintain you want to save your family and your marriage and keep in CLOSE contact with your exposure group... the people who support your marriage along side you...
Here's an additional thoguht from Penny Tupy :
Love As An Excuse For Infidelity
Penny R. Tupy 2003
So often in my work with spouses whose mates are in the midst of an affair I hear the anguished fear that because he or she claims to be, "in love" with the affair partner, it must mean that the marriage is over and the cheating lovers are meant to be together. Soulmates - because they now feel the intense passion of a fantasy relationship.
But of course they are, "in love." That's what an affair is. It's what the addiction is. It's an emotional response (without rationality, commitment or long term thinking) that causes us to do things that are not in our best interests and that hurt other people and destroy what we have worked hard to build in our lives - things like homes and families.
The idea that love should be the deciding factor is any of this is completely erroneous. As is the idea that love is some magical chemistry between two people. It's neither of those things. Romantic love really is nothing more than a mathematical equation. Spend enough time with someone meeting intimate needs of conversation, affection, admiration, and play time - and you will fall in love with that person. Assuming of course that they are not doing things you find offensive or objectionable at the same time.
The interesting thing about new infatuation/love is that we are blinded by the offensive or objectionable things at first. I think the pleasure of having needs met by someone new captures our attention to the point that we block out the less desirable traits. But like any addiction, what worked at first to create a high soon becomes not enough - we want more. When that happens in romantic relationships the irritating things seem to grow in proportion as the pleasure from getting needs met slackens. Unless real change takes place at this time - unless the real work of building a relationship kicks in - romantic love will wane.
This is when the instinct to demand more, to be rude or even to lose our tempers takes over. This is when the internal shift from, "You are so wonderful, what can I do for you," to "You aren't doing enough for me and I'm not willing to do anything for you - you jerk," occurs. This is where real marriage happens, when we move from - feeling like it- to making the commitment to doing what it takes to craft a truly connected and compatible relationship. This is where real love is grown.
For those, who have never honored commitment when the going got tough this is where they begin to bail. So, yes, I am sure that affair partners are in love. Does that mean it's the right place for them or that they have met 'the one'? Of course not. It means that they are in the habit of going for the feeling rather than committing to doing the work of making a truly successful relationship. Unless something greatly changes for these men and women, they will do the same again, and again. They will not find lasting happiness until they get it that marriage is more than feeling. Being in love is important, but staying there is what separates the men from the boys.
Be an advocate for marriage. When you hear of infidelity, take a stand. Refuse to condone affairs and "friendships" that threaten the integrity of the marriage bond. Educate your friends and families on the seriousness of becoming involved outside the marriage. Love is not an excuse for betrayal and abandonment. Love based on that foundation is like a house built on sand.