Being “opposite” is mostly not an advantage when it comes to relationships, with the exception of certain combinations of personality, especially strength and warmth of personality. A decent level of similarity is essential when it comes to most other aspects of personality, such as kindness and work ethic. When it comes to values, similarity is important, and the greater the convergence the better. When it comes to personal features, difference is not ever a plus, but most of the time they are easy areas for compromise.
If you have a strong personality, you don’t have to change (and really, you can’t change). You do need to recognize how others perceive you, and perhaps adopt more moderately adjusted behaviors – especially when dating.
Don’t marry someone with the hope that they will change. As much as you may wish it, people don’t easily change their attitudes and core beliefs. Rather, think: Would you marry the person as they are? If the answer is yes – but you would rather they change this thing about themselves – then you have nothing to lose. If the answer is no, then this is not a compatible match for you.
What is most important for a marriage? A couple needs to be compatible when it comes to personality and values, but can sustain much great divergence when it comes to personal features.