Having friendships among yourselves as men, as you get older, is exponentially more effort than anyone ever admits to, because everybody is so darn busy with work, kid crap, stress, and whatever issues their backs decide to throw at them at any given time. The only game I know that's really, really panned out for me is to pick a monthly check-in, no big deal, maybe just coffee, a work-out, or even a phone call and stick to it. Now, it's actually happening, as far as plans go, as opposed to 'we should grab sometime,' which automatically goes to never, because men aren't great at maintaining relationships, period, much less emotional relationships, but at least this is something set in motion, as opposed to waking up to finding yourself connected to everyone in LinkedIn as a friend because, apparently, they're people, far as anyone's concerned, anyway.
I choose a different friend each month and send a simple text asking if they want to grab a beer or coffee that week. That's it. The system works because it doesn't rely on advance planning or forced interactions--just one ongoing connection at a time. One of my closest college friendships has lasted because of this. Even as we've had kids and life has gotten busier, that weekly text has brought us together multiple times. We've found that people connect in ways beyond traditional social activities. Our bond has deepened through watching TV shows together and helping each other with household tasks. The key is that both people feel the connection and keep it genuine.
Just make sure to talk about things besides work, wives, and sports. Metaphysical conversations, life lessons, existence questions - don't be afraid to go deep into your friends, and let your friends go deep inside you.
One practice I have relied on to maintain my bonds with friends into adulthood is having regular meetups, rather than saying "let's go out sometime" with no real plan to execute. A regular breakfast, hike, or weekly check-in phone call removes pressure from having to have meaningful interactions each visit while keeping those relationships from being neglected. What works is the regularity. Guys tend to drift apart not because the friendship isn't appreciated, but because they are all busy, and no one wants to be the one pushing for meeting sessions. It's just that easy. By having something regular, all the hassles are eliminated, and the friendship remains in place no matter what is happening in their lives.
I have a group of friends that meet every few months for what we call our personal board of directors. We dedicate each meeting to one person's biggest challenge, whether it's professional or personal. That person explains their problem, and the others become advisors for the night. No small talk, just working through the issue together. I'm a physician, so I see what loneliness and chronic stress do to people's health constantly. Men especially get conditioned to handle everything alone. What I've noticed with our group is that this format doesn't feel like you're asking for help in the traditional sense. It's structured problem-solving, which makes the vulnerability easier. We give each other the kind of direct feedback you'd get in an actual boardroom setting. The friendships that come out of this go deeper than the ones built around hobbies or shared interests. Maybe it's because we're actively involved in each other's decisions and challenges. There's a sense of shared agency that changes how we relate to each other. I often recommend setting up a similar group to men as they start getting older.