North Node in the 7th House: Relationships as Destiny

Excerpt from my latest Sasstrology post:

"The North Node is considered by some to represent your destiny. It indicates (through its house and sign position) what you’re meant to do in this life. For those of you with the North Node in your Seventh House of relationships, this must mean that having one (or more!) committed partnerships is part of your destiny. If this is so, why are committed relationships such a challenge?"