Every person we connect with is part of our karma.  Some are very significant, like parents, children and marriage partners. Others are close, like good friends, but perhaps not central. And others are on the periphery of our lives, though no less important.  The karma we share has brought us together again.
When we shift our energy, the connection changes and these people we are karmically connected to may not recognise us any more, so they either go with us, or they reject us. It's up to us to set the intention and envision the kind of relationship we want -  we always have a choice.

Quoted from Discovering your Soul Mission by Linda Brady and Evan St. Lifer

“All the relationships we enter into - including those involving soulmates - are karmic. By initiating a relationship, we set in motion a soul contract with that soul to learn a lesson and resolve an issue from a previous life. A soul mate represents a karmic relationship that we have resolved: a deep conflict that has been settled, an obligation that has been fulfilled, and love that has replaced fear and anger.

We recognise a soulmate by the supreme level of comfort and security we feel with that person. That doesn't mean that there aren't issues that remain to be ironed out. Rather, it means we know intuitively that we can resolve issues with our soul mate without losing his or her love and respect.

When feelings of abandonment and betrayal arise with a soulmate, they do not last. Once soulmates achieve an ultimate level of symbiosis and serenity with each other, it remains forever.”