Tell him to grow up. I had to answer this one as I have never seen it with adults.
Why would you go out with someone who has tantrums? Tell him how you feel and that he needs to get his act together.
Someone who doesn't get their own way and resorts to tantrums needs a good hiding. They have been ruined by their parents and are used to getting their own way. If he is your boyfriend and cares for you he wouldn't tantrum.
Relationships are give and take and if he is tantruming on something he wants It would raise alarm bells. He will never change as he will always be selfish in his thought process.
Introverted people like calm and silence. They are people who seek to reflect on their environment and take life with more passivity, time to experiment and reflect on experiences. Of course, relationships are included in this premise. Therefore, you must have patience.
These types of people do not usually talk about themselves. At the beginning of the relationship there may be a conflict for them to express about their own life. In addition, they are people who tend to be very reserved based on their environment and experience.
You must take into account that before reaching the confidence you want, the layers will gradually be detached from who they are. The fact is that privacy is very important to them and they do not trust people with the naked eye.
Never make an introverted person feel the center of attention. That is one of the worst mistakes you can make. For them, personal space and discretion are very important things. Respect must exist so you must be understanding with your personality
If you like an introverted person you should take into account if your personality is compatible with yours to avoid bigger problems in the future.
If the person tends to have a bad character, give him his space, but if he becomes toxic and enjoys being alone with you, it is better to let him grow in his loneliness.
Us introvert men sure do have tantrums sometimes!
How best to deal with him?
Well, maybe he wants to be left alone, or maybe he wants to be loved.
One thing is certain, he doesn't want to be yelled at, or minimized.
Maybe start with giving him some space. Most introverts are empathetic. He will come around.