Emotional infidelity? Or just a close friendship with another woman?

Question: What makes a relationship emotional infidelity versus just a really close friendship with someone of the opposite sex? I know my husband would never cheat in the physical sense, but he doesn't seem to acknowledge that there's other behavior that crosses a line.

Answer: The difference between emotional infidelity and a really close friendship is what it takes away from you and the value you place on it.

And that difference is why it's so important for couples to agree with each other about the amount of time they spend together.

If the time your husband spends with his close friend is time you want to share with him (within reason; marriage does not equal Siamese twinning), and if he shares things with his friend that he's unable or unwilling to share with you, and if you are upset at being excluded, then you have grounds to speak up — and a loving, attentive mate will listen. There's more than one way to address the problem, so the key thing is validating the concern and being willing to bend. Again, within reason.

The wording has to be so careful here, because here's an example of something harmless: Let's say your spouse has a hobby that doesn't interest you, and pursues it (and talks about it at length) with a good friend, and you are actually happy for the X hours of alone time this spousal hobby-nobbing allows you, and when your spouse returns you're happy to see each other, then, yay for all involved.

Question: A good friend of mine is about to embark on an expensive trip to see a man, an old friend she has not seen in 10 years, for whom she seems to have romantic feelings. He is a colleague of mine and just told me in an e-mail that he has a girlfriend.

Should I mind my own business or tell my friend not to take that trip? She has never come clean about her romantic interest in him, so maybe I'd be overstepping.

Answer: This is strange — I am smack on the fence here, to the point where I'm about to type something and then the argument against it comes to mind.

For example: Don't say anything, because she has never confided in you about any romantic interest, and "warning" her would be presumptuous.

Then: But it's an expensive trip and she might be embarrassing herself, so what harm would there be in making casual mention of his girlfriend?

Then: But who knows how serious he is with this girlfriend? For all you know, they're casual or drifting apart.

And: What if this trip turns out to be just what both your colleague and your good friend need at this point in their lives, even if it doesn't go exactly as either of them envisioned it?

I've apparently typed my way to a "butt out" answer, especially since your friend is going to visit, not to war, and she is an adult who presumably can handle herself. But thanks for the exercise.

E-mail Carolyn Hax at tellme@washpost.com, follow her on Facebook at www.facebook.com/carolyn.hax or chat with her online at noon Eastern time each Friday at www.washingtonpost.com.