This week we received a proposal for a story about a man who was filled with hate. Labeled a romance it ended with his lady love moving on and leaving him. While any romance that ends unhappily is a misnomer, the real problem with that story was the main character or protagonist.
Almost always a protagonist is someone the reader will identify with, admire, and root for. Readers read in order to vicariously experiences other times and places, other lives, other people's problems. Almost always the protagonist will act from noble or admirable motives. If not the former, they must act at least from understandable ones.
That doesn't mean the protagonist has to be perfect. Certainly your leading character must have human flaws and make mistakes -- otherwise there's no story, only "happy ever after" and that's the end. But keep the character's motivation in making the mistakes in terms the reader will understand. If a wrong decision was made, the reader should feel as if they might have done the same thing.
It was no fool who said, "We are the sum of our experiences, not the sum of our possessions." It is your job, as a writer, to mold the reader's experience from the time they enter your story.