Isolation kills. Being alone, and feeling like there is no one that can help you is deadly. Women are good and not being isolated. Men are lousy at it. Especially once they get married. Thankfully, most of us marry our best friend, and our lover. The comfort and companionship that a man can find with his wife is unrivaled.
However, men needs friends. What happens when a guy needs to talk about his marriage? He probably does nothing. What happens when his wife is not suitable for the conversation, or to accomplish a task that she would not know how to do? Again, he probably does nothing, or calls his dad or his brother. We need friends. Just normal friends, like we had as kids and teenagers. Guys to hang out with, guys to talk to, and someone you can go to with anything, even if you never have, at least you know that person could handle it.
The often quoted, seldom practiced, standard verse on friendship:
Two are better than one, because they have a good reward for their toil. For if they fall, one will lift up his fellow. But woe to him who is alone when he falls and has not another to lift him up!