I would question the sincerity of a friendship in which one or both sides is repressing romantic feelings. Even if both sides have the best of intentions, that can't be a very fulfilling relationship for the person wanting more, no?
I don't think we're really disagreeing here.
For instance, I've also been married for about four years. Virtually all of my female "friends" are 1/2 of a couple with whom my wife and I enjoy socializing. My entire relationship with such women is defined as couple to couple; I would probably never go out to eat or catch a movie with any of them alone, not just to avoid the appearance of impropriety, but because it's simply outside the bounds of our relationship.
Every time I've ever been caught up in "friendship" with a female, romantic feelings on at least one side made sure it was anything but, and I've witnessed it again and again among my friends and family. I'm willing to accept that exceptions might exist, but I'd suggest they're rare.
Long story short, as general advice, if you find yourself in a "friendship" situation with a member of the opposite sex, you should probably extricate yourself from the relationship as gracefully as possible; such situations almost always end poorly.