I've learned to free my emotions a lot more by studying Acting (by, for a few years, doing short acting courses as an adult whilst living in London): it turns out modern acting techniques - the stuff that roughly falls under the Method Acting umbrella - are all about feeling truthfully as if you were indeed that character you're playing living that specific situation, so essentially I had a pretty much judgment free (in terms of other people judging you) license to let myself go and fully feel and show it (as that "person" which was the character in that situation).
Curiously it also unlocked my empathy (which turns out to be so high I'll literally yawn from seeing animals yawn) though I'm not sure if my blocking of most of my Empathy until then was due to social expectations on how men are supposed to behave or a childhood self-defense mechanism due to one of my parents being VERY intense and emotionally selfish (it makes sense I would block it merely not to constaly be overwhelmed by somebody else's rollercoaster of emotions).
All this even though I'm Portuguese and thus grew up in a culture were people are very expressive (compared to what I saw living in both Northern European and Anglo-Saxon countries, so think something like Italians), and all that expressiveness is backed by actual emotion (people really are enthusiastic or angry or saddened by what the other person telling you their story went through), though I would say that the range of emotions men are socially expected to express is limited to mainly positive emotional states or anger-related emotions.
Anyways, just my 2c as I think it's an unusual point of view and maybe food for thought.
PS: One of the things I learned in Acting is that not only does your body follow your mind but also your mind follows your body (really: if you have any ability for introspection try walking with a confident walk and see how it makes you feel. Then try a downtrodden walk or a fearful walk) which kind dovetails with the whole idea that if you're not expected to show certain kinds of emotional states you end up not feeling such emotions in day to day (except when you're overwhelmed by it and it hits you like a ton of bricks).
As a Portuguese (that has also lived in a few other countries in Europe) I would say that it's more that there is a range of emotions that men can express without that being frowned upon were certain things are still frowned upon if you show them openly (mainly around sadness) though for example openly showing tenderness for your partner or children is expected and even approved (unlike certain other cultures were men are expect to be distant).
Mind you, in some cultures the limits on expression of emotions or selectivity about which emotions you are expected to express is pretty high for both men and women (for example, the Dutch in general tend to refrain from expressing much emotion to strangers) and in some cases there is even such a strong expectation that you react in certain ways that it leads to people in general faking expressions of emotion (the English upper and upper middle classes are pretty big on showing the "appropriate" reaction independently of feeling it).
I would say (from contact with Americans and consuming some American media as well as having lived in England) that the expectations on what emotions people should be expressing are quite different and in England they're even very much defined by people's social class (for example, the "English Gentleman" is entirely a façade - all about what you show, not at all about what you think - and occupies the same place in terms of male behaviour expectations for traditional old-money upper class English men as the bossy slightly-angry assertive go-gotter seems to occupy in the US).
So far I generally have seen a tendency for frowning upon grown up men expressing sadness for themselves (though in some countries, not for expressing sadness in empathy with others and their pain, especially if they're close family) and have also noticed equivalent expectations on the expression of emotion by women (for example, it seems to me that middle and upper class English women have a massive weight of social expectations on them in terms of what they're expect to show to others - including the emotions they express - in lots of situations, and a lot of it is about reacting with the "appropriate" emotion in some situations even if they don't feel it)