Funny timing. During our vacation last week, my son said that he never sees me cry. He said he cries, and he sees my mom cry, but that he doesn't see me to it often.
I let him know that I do, and that it's healthy to do it when you feel like you need to. It's just that I don't cry when I fall, or that something doesn't go my way, or someone says something mean to me.
Basically, my emotions are mine. Other people's emotions are theirs, and everyone, everyone, everyone, cries. I just don't cry because not as much bothers me, but man, when it does, it really does. And I let him know that I'm a happy crier too. Movies, songs, even games.
We can do our kids, and ourselves, a favor and teach them that being a "man" doesn't mean "never cry be strong fuck all the bitches make money". Being a good person, with integrity, confidence in yourself and your likes/interests, and a good work ethic are what to aim for. And you can't have much of that without processing your feelings. Crying is natural.
If you want to take it one step farther, you can always say that the bigger man is the one that doesn't feel like he needs to hide his feelings.