I think that unfortunately it is common.
When we were newly married our communication was not good at all - now it is better (not perfect, often it still is a problem but better).
I think that there are some things they never discuss with their spouses (but only with other ones with similar experiences) because the spouse just does not understand - but apart from that it is important for them to talk about things, about how they feel and they feel better after they did - but at the same time it is difficult for them and they might also afraid to be judged.
What can we do? I think we can tell them that they can talk to us when ever they feel like they need to or want to but at the same time not force them to. Find out what makes it easier for them to talk... for example my guy likes to have a drink and likes to do something different... like watch TV or repair something or clean something... he doesn’t like to look you in the eye when he talks about some things. So he stares at the TV while talking about difficult stuff. Sometimes he also likes to cuddle and be held.
My advice is: Find out what makes it easier for him to talk about things (for example if his hands have something to do, if he does not look you in the eye, if you cuddle him, if you hold his hand, whatever), if there are certain places or certain ours of the day he likes better for talking and then ask him if there is something he wants to talk about.