When your man is sensitive to everything you say or do, you will need to change the way you communicate if you want the relationship to work out. He may be going through temporary problems at work or with some other activity, so giving him some space might be all that's needed. But if he's consistently sensitive and has a hard time managing his feelings, you might need to let him work things out, or reassure him that you want to support him.
Talk to him with a gentle tone. If you're too abrupt or stern, you might startle him. Smile a lot to reassure him that there's nothing to worry about.
Be supportive. If he reacts negatively to something you say to him, tell him that you didn't mean to offend him and that you don't want to hurt his feelings.
Massage his ego. If he is overly sensitive, he may be lacking confidence. Tell him that you think he is good at his job, or tell him another compliment, then he will have more confidence and not be overly sensitive to what you do or say.
Let him initiate conversations when he feels inclined. Many guys like to keep conversations brief, and many others don't like talking often, so allowing him to initiate dialogue will put him more at ease.
Don't be invasive. If you constantly ask him "What's wrong," he will likely react negatively. Instead, give him the time he needs and maybe he will come around.