How to keep the passion alive in your relationship, according to a relationship scientist

Eli J. Finkel, a professor at Northwestern University and the author of "The All-or-Nothing Marriage," explains how to maintain fiery passion in a relationship. Following is a transcript of the video.

Eli Finkel: I'm Eli Finkel. I am a professor at Northwestern University in the psychology department and the Kellogg School of Management.

We want our spouse usually to be our primary source of emotional support. So, I want to be able to come to you when I'm most vulnerable - when I'm most pathetic and weak and hurt.

And I want you to support me. And that's great. It's one of the great things that we can get out of a meaningful marriage.

The problem is it's not particularly hot, right? Like, when I'm coming to you with my tail between my legs and just feeling weak and defeated by the world, you're probably not thinking how desirable I am.

You're thinking of how much you want to nurture me in the way we might nurture a young child.

On the other hand, when we want to have sexual passion in the relationship, there's another way that we like to connect with each other.

So, there's this interesting juxtaposition of we want to have a respectful, loving, warm, nurturing sort of connection, but we also want a little bit of naughtiness and impropriety. And reconciling those two things is difficult.

But it isn't impossible. There's been some excellent research coming out over the last decade that looks at the importance of engaging in novel and exciting activities together.

A lot of us default to engaging in comfortable sorts of activities together - sitting on the couch and watching some nice television for example.

And that's good for the relationship too, especially if you're having some communication while you're watching. That tends to increase the amount of satisfaction and connection we feel in the relationship.

But it doesn't tend to increase how much fire and passion we have in the relationship. What does that is engaging in novel - that is new and exciting sorts of activities that we haven't tried before.

Examples might include ballroom dancing, going hiking/ one person in one of the couples listed shucking oysters for the first time. But things that get you out of the mundane reality of everyday life - this is one of the most promising recipes for helping to sustain a sense of fire and passion for the partner.