For me it is another story, I went tru too much to feel comfortable with someone.
But here is the reason that I keep hearing why men are afraid of commitment.
Trust: One of them is the fact that more and more women misuse their power, cheating, lying, manipulating. And time and time, when a men speaks up about it, he gets laugh at and the women says that it all the men's fault and the average person just believe the women and always questions the men. The man is guilty in the eyes of others until proven innocent, and sometimes not even then. Young men see this when they are growing up from the men around them. So they are afraid to give a women this kind of power by trusting them, so they are quicker to move on, even if they like the women they are with.
Worth: Most women are not worth it nowadays. I mean in value. Since women are more and more encouraged to sleep around, they become unattractive. Why?! If you sleep around, you perception on men just changes, you never had the chance to learn how to build a healthy relationship, and you loose social status. This is what we call baggage, and that is not really attractive, so men are not quick to call that type of women a wife. Unlike popular believe, men or women, if you sleep around a lot, your perception changes where it will be harder to have a healthy relationship. For women the consequences are worse.
Love: A lot of men learn the hard way about how women are wired. Women are always looking for a better partner, even if they are in a relationship. So they are always on the lookout, and when they find a better men, they and the relationship and go to that other men. That is why you might hear, " she is not yours, it is just your turn ". That is because it is a question of time of when she is going to end the relationship. Men know this so they don't care to commit to someone who is planning to leave him from the start. Women don't love men anymore, they are always choosing the best option they can get at the moment. Women don't love men anymore, it is all about fun.
There might be others reasons, but these ones are the most spoken, the most basic. The third one is the most know by young men, they experienced it by that time a lot.
(I waited so long to post this, with the steemit updates I couldn't do anything, hope it was worth it)