I disagree that there's anything not to be "tolerant" of.

They're Not Married

Make sure it's clear from thes start that you are not being exclusive.

Look, he's not married to her, and dating is not a "miniature marriage". Maybe Dakota felt that her relationship was very serious, and so she feels that all courtship is. However, that doesn't mean that this relationship was developed to the point that warranted such exclusivity.

It Was A Hard Lesson

I agree with you and I think you make a lot of sense.

A marriage is the community's acceptance and approval of a relationship. Dating is just a state where people are trying to figure out what their relationships mean to them. He obviously wasn't sure, and so he looked around. In looking around, he discovered that it meant more than he had expected. Does that make him evil? No, it makes him curious. It makes him unsure. And what was the result? He found out what was important to him. It sounds like growth, to me. It sounds like the kind of hard lesson that one has to go through in order to build a relationship.

Commitments Are Constantly Tested

I've been married for 7 years. I adore my wife. Neither of us has ever been unfaithful. However, our commitment to our relationship has been thoroughly tested every step of the way, and it continues to be tested. Only by looking back on a long history of choosing to be together rather than apart that it becomes apparent that we both derive fundamental satisfaction with our marriage Relationships are not static. They continually change, even in good marriages. Commitment is not binary either.

Indiscretion Is A Sign

Should he tell her? I guess that depends on what he expects this relationship to become, and what his and her commitment was at the time of their separation. This relationship probably has a lot of growing to do before it will amount to anything. I don't think it's safe to assume that telling all will necessarily be productive. I also don't think it's safe to assume that it would be inappropriate for him keep it to himself. Perhaps he should instead take his indiscretion and feelings as a sign that it's time to make a concerted effort to determine what the relationship means, and let the conversation about their commitment develop naturally.

-- Reid