Ok I’m normally a lurker but have to post. When would he have had time for friends? Have you never known someone who was dominated in a relationship? The outgoing extroverted one is always planning my activities and always on the go. He wants to stay after work and get a beer? No expected home to watch the kids or go to mutual friends for dinner. Go on vacations by himself? How? When? It takes continual effort to keep close friends, and much harder if you are introverted. And once kids come along, so much harder and so much effort. Again read about introversion, whereas extroverts derive energy from other people, introverts find it very tiring to socialize. If you’re working all day and taking care of house and helping with kids and socializing with mutual frIends and you’re introverted, who wants to do more than that?
Again, all my opinion.