Eh, I don't think EVERYONE is struggling with this. I am an introvert, and have no desire to go out and do more things with friends. I get enough socialization with my wife and kids, and don't really have the desire to do more things.
I used to think that way. Then, divorce, custody battle and the dark abyss. No home, nobody to talk to; just silence, loneliness, general apathy of the world around you. It's the trap of the middle-aged man: to focus on work, invest in family, and hope these things will be a constant because you are doing the right thing. We don't have enough emotional bonds, don't know how to create them, and if the wife leaves and takes the kids, there's nothing left.
I'd use this as an opportunity to do something exciting with your life (if finances permit). Go live in Asia and do the nomad thing, if you're lonely there are a ton of Filipinas who want nothing more than to be a good wife and provide for their family. Try to start a business, take up some kind of art and make an honest effort to get GOOD at it, etc.
Eh, I don't think EVERYONE is struggling with this. I am an introvert, and have no desire to go out and do more things with friends. I get enough socialization with my wife and kids, and don't really have the desire to do more things.