I'm new to this forum, but your post caught my attention as it's one of the main areas my wife and I struggle with.
She is fairly social. She grew up in a big family (7 brothers and sisters) and loves to talk and play games and whatnot with others.
I was an only child, grew up in a rural area, and have always been happier in solitary pursuits than socializing with others. I think I'm a friendly, easy going guy, and have no problem making friends, but I moved around a lot when I was young and just learned to be content on my own. These days I run my own business out of our home, and have plenty of other activities (woodworking, home improvements, auto repairs, etc.) to keep me busy, and when I have spare time I prefer to watch educational TV programs, research various topics, or surf the net.
While I've had a few friends over the last 20 years or so, we just don't keep in touch. They have their lives, and I have mine. My closest friend is probably a buddy from high school (30+ years ago), but we probably only see each other every 5-10 years or so. I've never "gone out with the guys", nor do I have any desire to.
For that matter, I don't have any close family either. My father and grandparents died many years ago, and my mother has her own issues and cut off contact with everyone. I haven't heard from her in years. Her loss. The rest of my family (cousins, uncles, etc.) live on the other side of the country and we were never close anyway.
Of course, my wife seems to crave social interaction, so I have "tried" to accompany her on occasions to various events. Unfortunately, it's a very uncomfortable situation for me. I have no interest in sports, don't relate to the usual work banter, and generally have nothing to make small talk about. I usually sit there bored to tears, thinking about how much time I'm wasting on gossip and general nonsense, when I could be accomplishing something productive instead.
On the other hand, I LOVE to spend time with my wife. I enjoy taking her out to dinner, watching movies together, working on projects together, going for a walk (which we rarely do), or just talking (which she says I don't do enough of). She's my best friend and all the social support I need or want in my life.
The ONLY time I regret not having at least one friend to turn to is when my wife and I are having difficulties. I really have no outlet when I need to vent, or anyone to get another viewpoint from. But those occasions are rare so it's not an issue 99% of the time.
Obviously, we don't have dinner parties or any of those kinds of social things, but she tries to get together with friends on her own every now and then. More often than I like, but not as often as she would like. But, I realize SHE needs social interaction, so I "try" to be understanding. Still, that's the one area we struggle with in our marriage.
Anyway, I don't have an answer for you, I just wanted to offer a view from a fellow loner. It seems we're often labeled an outcast or need some kind of counseling because the social world seems to think a loner must have issues that need fixing.
Compared to me, maybe your husband won't look so bad...