Dream wasn't good with love. He found it useless. It would always end one way or another in his mind. It would always end in pain and sorrow.

But then he met you.

You were the exact opposite of him. You were happy, outgoing, optimistic, and you always saw the good in people. He fell hard (though he would never admit it). It was concerning to him how much he cared for you. He shouldn't care this much about a mortal.