Why do covert narcissists struggle to see things as both good and bad, and how can you test this trait in someone you're uncertain about?

How do Sagittarius rising people typically handle negative relationships with siblings and friends, and what advice can improve these interactions?
How do I end up with a super dominant man if I’m really dorky and nerdy and awkward and inexperienced and shy? He’s very stern and I’m so insecure and I just start shaking.