One thing to think about is how in our culture, we are taught to manifest our relationships as sort of contained & condensed into themselves, ever smaller. I love her so much all I can think about is her. All I wanna do is spend time with her. We spend less time with our friends so we can talk all day every day. Etc.
Instead, it's possible for a relationship itself to extend outwardly in the form of your other connections. When I meet a new girl, my relationship with my domestic partner is expressed in everything I do with the new person. My partner's light shines through in the new relationship. It wouldn't be the same without her, *I* wouldn't be the same without her, and everything I do is in the spirit and honor of what we have. She is my rock, my foundation on which other relationships can grow. The new connections don't have to take away OR have "no effect" on the existing one -- they can add to it.