You would want to talk to him (make a specific time for this) Ask him to please give some examples of what is it that you're doing or not doing that is stressing him out.
Try to be open to the feedback.
It is possible that he is having other problems maybe at work (that he is displacing onto you)
Remind him that you care about him and point out to him that it takes two people to make their relationship work. Ask him what he would do on his end and what is it that he is expecting of you.
If you're open to couples counseling, let him know that is an option.