Advice?

A friend of mine has been going through a rough patch lately, and I’m not really sure how it is that I should respond to him or support him emotionally. He got married a few years ago, and his wife goes to college a few states away. She doesn’t want to transfer to a more local college (and maybe she shouldn’t have to, of course), and he can’t leave his career. They have resigned themselves to a distance-marriage with frequent visits to each other.

Unconventional, but not that terribly strange, right?

Well, recently, things have begun to get weird. She doesn’t wear her wedding ring because she says that guys try to hit on her when she’s wearing it. Even though my friend and his wife have had discussions where they agreed not to use birth control (since they would like to have children), on a recent visit to her, my friend found birth control pills that had been taken regularly. On that same visit, a friend of the wife told my friend that another guy had been getting pretty close to my friend’s wife. She also stopped listing herself as married on her ‘myspace’ page.

During the summer break from classes, my friend’s wife told my friend that she was going on a month-long business trip for her job that would entail extra pay, but that he wouldn’t be able to get in touch with her for most of that time. When she came back from her trip, my friend surprised her with a special visit at her home as a ‘welcome back’ present, and noticed that she had a red mark on her neck. She explained it as being a bruise from where a kid had shot her with a BB. Strangely, hotel and rental car charges appeared on the credit card account shared by my friend and his wife, and the extra pay from the business trip never materialized. The charges, she contends are mistakes and she is pursuing the credit company to have those charges expunged, and she says that the extra money is being held up by the red tape of her company.

As the last straw for my friend, he discovered that his wife had e-mail accounts and instant messenger personas that he didn’t know existed before, and found a posting on an internet forum (posted only days after her business trip) wherein his wife explicitly says that she met a guy online, that he flew in to meet her at her university, that they spend a few weeks together, and that she fell in love in spite of herself.

My friend’s wife is alleging to him that none of this stuff means what he thinks it means, and that she might be a compulsive liar (so not to trust what she said online).

Here’s the rub. She’s coming to visit soon, and I already know of at least one social function where I’ll be forced to interact with both of them together. How should I play it off? I want to believe that there is an innocent explanation for all of this, but I’m finding that innocent explanation harder and harder to believe. I don’t want to think badly of her, and I don’t want my friend to be hurt if it turns out to be what he thinks the evidence points to. What should I do and how should I act?