This happens to DH and I sometimes. We get in ruts where there is nothing I have to tell him about and nothing he has to tell me about. He is the same way with cars and I could care less. I have told him that I don't understand cars and have no desire to understand them. I support him that he wants to fix them but that's all I can do. We are also the same way when we go out with friends, very talkative and outgoing but sometimes at dinner alone there isn't much to say. I think I am at a point to where if he seems to be moody I dont even bother initiating conversation bc he gets fresh and then I'll bark back.
I bridge the gap by asking him about how his car restoration is going, talking about my day at work, family, or future plans. He doesn't car about the books I read and I understand that so I don't bother bringing it up.
We hit this rut often and yeah it bothers me a lot. I just try to fight through it.