Well, there is nothing to condemn about a close, personal friendship.
But is it not also possible for a brother and a sister to have a deep sexual relationship? What about a married man and his mistress? Yet the fact that the relationship is "deep" and has a "caring" aspect to it would not change the sinfulness of having a sexual relationship that violates the bonds of matrimony. And while may be anecdotal exceptions to every rule (like the one you demonstrate), hard facts show that, on the whole, homosexuality is not a healthy lifestyle for individuals or, more importantly as far as law is concerned, for society.
For one thing, the 1-2 percent of the population that is homosexual is estimated to be responsible for 20-30 percent of all incidents of child molestation. For another, homosexuals (especially men) are often on average far more promiscuous than their heterosexual counterparts. Third, even in places where homosexuality are more tolerated than in America, homosexuals have higher-than-average rates of depression and suicide. To give legal recognition to homosexual unions or marriages would essentially be to give a sign of approval toward such relationships.
Now, for your particular case. It is easy to blow the whistle on our friends when we see them actively destroying their lives, but in your case, there aren't any apparent consequences that you can discern. I know from experience that that makes it harder to condemn their behavior. I'm not, of course, suggesting that we gossip about them or attempt to pass judgment on the fate of their souls; that is the jurisdiction of God alone. But I also know from experience is that not taking a stand on moral issues because a close friend is engaging in illicit behavior leads one to think subconsciously that such behavior is harmless. Eventually, their behavior might pose a temptation to you. I learned that the hard way.
Jesus ate with prostitutes and tax collectors, yet he extolled the virtues of traditional sexual relationships and firmly condemned dishonesty. The best advice I can give to you is to follow Christ's example. Be kind to your friends, but don't pretend to give approval to their illicit sex. Pray for them and live your faith before them. Make them hunger and thirst for what you have.
BTTT!
Since my posts #11 and #15, I have learned that a former partner of an old gay friend of mine recently suicided. (My friend was very distressed even though he was no longer in touch with the unfortunate fellow, whom I never met.) So while I might contest some of your numbers, MegaSilver, your points are well-taken.
Yet, I still am reluctant to condemn my gay friends who are in long-term stable monogamous relationships. I feel a little like Huck Finn, who decides not to turn in his friend Jim, a runaway slave, even if it means going to hell.