What have you told him exactly?
There's nothing wrong in communicating what you think it isn't all right in your relationship, but you need to tell him exactly what you think it is wrong?

He seems he has lost some motivation (at least from my point of view), that's why he does nothing but work.

Try to speak to him and tell him how you feel (as calm as possible) and make him know that you want him to get better, enjoying himself and your relationship.

Communication is my advice. Be safe, and good luck