A few personal thoughts, if it’s not too much…
I don’t think any of us knows enough about the OP’s situation to be able to say whether his friend’s confidence in him is putting anyone into any dubious ethical situations…I think it’s entirely possible, even laudable, for people of the opposite sex to have close friendships without any trace of temptation towards adultery. Sure, the OP should be careful, but now that we’ve raised that issue already…I don’t think we should presume that women should only be able to seek advice from other women.
At the same time, nor do I feel that any friend’s advice, no matter how good a friend that person may be, is a fitting substitute to professional help (if the situation is really that bad) or, especially, to open communication with her husband. (On that topic, I agree with Becks’s point that the couple should be making decisions together.)
One other thing I will add…hopefully, ARFF, you are right that your friend’s husband isn’t suspicious, and has no reason to be suspicious, about your friendship with his wife. But with all due respect, I do detect in some of your posts a personal leaning towards divorce as a permanent solution to this (in all likelihood, temporary) problem; and that is something that I think your friend’s husband could rightfully be upset over. I know from experience that things can get really ugly when someone suggests divorce to a married person behind the spouse’s back. I am a Catholic and I believe divorce is wrong, but even putting those personal beliefs aside, divorce is something to be discussed within a marriage and within a marriage, alone. No matter how well-meaning you may be, I don’t think it is anyone’s business or right to come in from outside of a marriage and suggest that kind of thing to a woman behind her husband’s back…to presume to know what is best while the husband is not around…to plant those seeds of doubt, which can only fracture the marriage. In my mind, that definitely crosses some sort of line.
That said, many apologies if I am reading too much into your comments or misunderstanding where you are coming from. I think it’s great that you are doing everything possible to be there for your friend, including respecting her religion enough that you would seek advice from other Catholics. Best of luck to all three of you in this situation.
Peace,
+AMDG+