Your partner has a strong effect on you, mentally. When you're together, your thoughts, ideas and conversations take on a deep sort of intensity -- you might talk about life's larger complexities, such as sex and death, or the intensity could come out in the way they treat you. They might try to dominate the conversation, or even your way of thinking -- especially when things veer toward small talk.
There are too many big, life-and-death issues to discuss to waste time chitchatting! But you're interested in these intense conversations as well. When your partner has an idea that's abstract or otherwise complicated, you're able to give it rational expression. Sound complicated? It is! Your effect on each other can be profound; you likely understand your partner better than they've ever been understood by a lover, and they move you on a deeper level than you've ever been moved. You both give access to the other's deepest, most complex thoughts. If you decide to work together on a business or creative project, this is a really advantageous connection, because it allows you to access the depths of your partner's ideas and bring them out to light. But even in your day-to-day interactions, you can feel the effects of this pull between you. You can broaden each other's horizons by introducing subjects the other might never have considered before. If your relationship has any issues to solve, this aspect could help with that, as it encourages you to talk things out in a serious and thorough way.