Does he actually enjoy being asked?
I really loathe small talk like this!
I've spent years training first my parents, then friends and partners to not ask me things like this.
If I have something I want to share/tell you, I will. If I don't, I don't want to be asked - maybe I had a really shit day and don't want to think about it any more!
Likewise, if they have something to share, I expect them to be proactive and share it/say what they want to say, not be oddly passive-aggressive and sit there silently expecting me to do something they've never expressed that they want me to do.
I totally understand that to you, @Emerald95 , it's a way of showing interest and love. And that's absolutely fine and you're absolutely entitled to ask for what you'd like in a relationship.
But other people are different, and your judgement on your DH assumes that he sees the world and this interaction in the same way as you. He may very well not, and therefore not think that this is making "polite conversation", and not mean anything at all by a failure to reciprocate.
If you'd like him to ask about your day, tell him that, and that it's important to you!