All the things that are most fun to do together as a couple -- traveling, even if it's just going to the next town over to eat lunch and hit the antique shops; talking about your beliefs and your dreams in life; reading books or watching movies together -- also helps you both in terms of expanding yourselves and grabbing hold of opportunities. Your partner, especially, introduces you to new ways of being that surprise and delight you, and that definitely expands your horizons for the rest of your life, regardless of how long your relationship lasts. Risk-taking could be a focus between you -- going skydiving together isn't out of the question!
But you can also keep things simpler by taking a class together or going to see plays and discussing them afterward over a cup of tea. You both find a lot to like about the way each other's minds work, but you, especially, get a lot out of your partner's particular brand of intellectualism. They feel comfortable with you, too, as if you just get all the ways that they look at the world, and the things in their thinking that make them who they are.