Give some examples of some arguments you may have had that was recurring throughout the relationship. Anger tends to stem from those problems that keep reappearing in the relationship because they aren't being fixed... either because they can't (fundamental flaws in personalities) or one or both simply aren't taking the steps to solve them (pride, laziness, or ignorance gets in the way).
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen