Yes this is a frustration I have with my male FWBs at the moment. He sucks at communication and against all odds, I try to get him to open up. Interestingly, he opens up when we are arguing to one up me or when I become more distant from him. ughh super introverts :/

Lets see, does teasing count. We teased each other a lot and often said the opposite of what was expected. Like did you miss me? Were you gone? Often when she was gone (she was gone a lot) I would make a nice meal for when she returned. Sometimes she would ask, when are you going somewhere? When I did she told me the first few days it was nice having some alone time but then after that she missed me. It was exactly the same for me.

To answer some of your questions, I explained more in my post.

What I will say is not what I thing is right, it's simply observation of the average and most common.
Men are taught to never show feelings, to never give the others something to explore. It is difficult to change this stonewall behaviour.
More than that we are trained to take care and protect first. And that's how you show the feelings.
If you are in pain or feeling bad, go take care of it by yourself, don't bother the ones you love and don't show a possible competitor that you are in a weak moment.
When you are feeling good, distribute your happiness with the ones you love.
This is hammered down since childhood, a 30 years old man can try but he will never be completely free from this process. The only hope is the next generation.

To a certain degree men are taught not to cry. We have to be stoic and be able to handle what life throws at you. But there is very little training about how to do this.