Someone who is overly possessive is the worst partner to have.
Being an only child means you're accustomed to being independent, which suits you just fine.
Truly, you are a unique individual who can support yourself and stand on your own two feet.
Marrying someone who is clumsy with their own life is the worst possible choice.
You learn to take care of yourself and those around you early on in life if you're the eldest kid.
However, you should try to avoid being the one who has to solve everyone else's problems all the time, especially your partner's.
This in no way implies that you are unable or unwilling to provide assistance.