A 'good relationship' is supposed to enhance your life, give it somethgin extra that you don't have to have, but that adds to your life.
It certainly shouldn't have you unhappy.
Your own happiness is your responsibility, of crouse, and you will never find it from someone else, but with the right person you will not be prevented from finding your own happiness and contentment.
Having spent many years single and content with my life, I know I certainly don't need DP, I choose to have him in my life because he brings a whole lot of extra stuff to my life that I choose to have in my life. He isn't responsible for my happiness though and I am not afraid that without him I wouldn't be happy.
A relationship, whether with a partner or with a fiend, has to add to your life or there is no point in it. Even a friendship has to be beneficial to you, or it isn't really a friendship is it?
With my DP I feel easy, content, I have a companion and frined that knows me better than anyone else, I have someone to share everything with, who makes me laugh a lot, who does little tihngs that are lovely, who does big things that are lovely, who shares in the mundane boring chores of life, who is always there for me. He doesn't give me stress, anxiety, issues, isn't horrible, doesn't insult or put me down, isn't selfish and mean. My life is better with him in it.