He’s so immature. I would never be able to deal with someone like that. FYL OP

There is a reason men never cry sweetheart. Because when we do nobody cares and it makes life worse. The only flaw with his plan is he is not supposed to tell you about it. If you want him to open up readjust your attitude and do not take him opening up as an opportunity to "fix" his mindset / your issues. Be a safe place for his emotional vulnerability and he will be very loyal in the end.

Sounds like a pretty good strategy to me.

While stonewalling on the part of a man in a (heterosexual) relationship is one of the strongest indicator that a relationship will fail, it's usually not the first step. Most failed relationships are partly the fault of both individuals. If it was like this from the beginning of the relationship, hopefully you realized quickly and got out. If, however, it's something that occurred over time, it's likely the result of other unhealthy behaviors. The commonly cited ones are criticism, contempt, defensiveness and stonewalling. If you've been constantly criticizing and nagging him, or demeaning and criticizing his ideas, or getting angry and defensive every time he suggests something you don't agree with, it's natural for him to shut down and avoid anything to try and minimize conflict. In that case, it's both of your negative cycles of communication that has lead to the failed relationship.

His behaviors could be the results of being raised in a toxic masculinity environment.(that's the don't cry ever,be a man ,suck it up kind of environment) that a lot of men end up being raised in which makes it very hard to impossible for them to communicate their feelings, wants and needs. if you love him seek couples therapy so that you can both learn how to communicate. and try to be patient with him many men are raised to believe that if they let their feelings out they will be ostracized, alienated by other men or will be told they have anger issues by women. when all they're trying to do is express what they're feeling because many men have not learned what their feelings are because they were always told to suppress them. this doesn't have to do with their maturity it has to do with their understanding of their own emotions.

OP - I realize you want and need more emotional engagement. But this is not the worse case scenario. He could be a violent abuser (either verbally or physically). Try to have some appreciation of the fact that this is not as bad as that. Also try to understand that many men are raised to suppress demonstrations of emotions as that is perceived as a weakness by many in man-world. If you want a partner who is just like you, you are going to be disappointed. I personally think that if the two of you are willing to work on the relationship it can be improved. But don’t be surprised if your partner expects some improvement and accommodations from you too - that’s only fair. And your partner will always have the personality he has, but he may learn to be more expressive if he is comfortable in the relationship.

Dude needs therapy.

I mean, he is not wrong, his thinking is just too ahead of its time

So his moto is conceal, don't feel, don't let them know? Maybe he thinks the cold attitude never bothered you anyways.

And you were attracted to this distant emotionless person. Maybe re-evaluate yourself too.