What I was thinking so far: I get to know a lot of people. With some of them I become kinda like a friend. Most such "friendships" deteriorate over time; I don't remain friends with most people for a long time. For some unknown reason the relationship doesn't work out.
What I think I have found today: When communicating with a person becomes hard, I stop talking to them. Suddenly one day I decide I won't discuss serious issues with them. That's pretty much the end of that relationship.
Takeaway: Keep talking to your spouse. Even if you think/know that you would only annoy them.