If you count "having few male friends with whom you often spend personal time" as lonely, then I am definitely lonely. If you consider lonely to mean "feeling of a hole or gap in your personal/social life", then no. I am not lonely, whatsoever.

Different people need different amounts and types of social interaction in their lives. Where I'm at in my life, I'm very comfortable, happy, and content. Closing in on 40 with my wife and recently-adult child, and with the rest of my family (who I rarely see, as many are out of state). I have a small handful of male friends in other states that I see once or twice a year. Otherwise, I've mostly fallen out of touch with male friends, and that doesn't bother me. And that's me/personally ~ I'm not suggesting that this should or should not be acceptable to others.

Just saying: The threat facing middle-age men is loneliness (as the article states), not lack of male friends per-se. I fit the description of the men in the article, but I am not lonely now. Perhaps, in a few years, I will realize that my priorities change, that I am lonely then, and I will resent my 30s self for allowing so few male friendships to grow and flourish.