I'm not going to pretend that I know this answer.
I do believe that you can create happiness with a person by being tolerant, objective, patient and selfless. A pride comes form mastering all of that so it's not all about "them".
What brings true contentment with whomever shares your life is being totally content with yourself. the hardest thing of all to do, especially for people like us who haven't discovered that trick.[/font]