OronD is right and you should take comfort that a lot of newlyweds (3 years or less) go through this, whether it is a best friend, parents, siblings, etc.
The whole point of marriage is that you can lean on each other for strength. He's not leaning on you, so you have a clear message he doesn't trust you. So how can you trust him with anything you say as it will go beyond the confines of your marriage.
You need to lean on each other. This will take a great deal of work and you need to talk and listen to him about it. And you need to set boundries. You need to be a united front in your life together. If you can't do that together, what is the point of marriage.
I'm not saying that he or you can't let off steam and go to talk to people about marriage or little things in life. But there has to be boundries.