Love triggers all four happy brain chemicals: dopamine, serotonin, oxytocin and endorphin. No wonder it’s so motivating!

However, life is complicated because the happy chemicals are not designed to be on all the time. The job of this brain stew is to reward you for steps that promote your genes. They dip after they spurt, which is why we’re always struggling to get more. Fortunately, when you know how your happy chemicals work, you can stop blaming your partner and stop blaming love. You can better manage the neurochemical roller coaster when you know how you create it.

1. Dopamine surges when you anticipate a reward.

The joy of dopamine is the brain’s signal that a need is about to be met; but the dopamine is soon metabolized and the good feeling is gone. We are always seeking something because dopamine makes it feel good.

However, the harsh truth is that the brain habituates to rewards it already has. Something new is what it takes to stimulate dopamine. This is why the short-run joy of dopamine is not a great guide to long-term happiness. As you might have guessed, we crave it anyway because we’ve inherited the brain that motivated our ancestors to survive in a harsh world. You can train yourself to focus on long-run rewards instead of just on immediate rewards.

2. Endorphin is triggered by laughter.

Endorphin is triggered by physical pain. It masks pain with euphoria for a few moments, which facilitates survival action. It’s meant for emergencies, not for constant euphoria.

Laughing triggers a bit of endorphin as it jiggles your innards. It’s easy to see why love revolves around making each other laugh. We prize this endorphin feeling because it’s so rare. Unfortunately, it’s metabolized in a few minutes and you’re back where you started.

3. Oxytocin is triggered by touch and trust.

Oxytocin is the pleasure of social support. It’s released when you trust. We would love to have this great feeling all the time, but trusting everyone would not promote survival. Our brain is designed to make careful decisions about when to release it. Neurons connect when oxytocin flows, which wires you to turn on the chemical more easily wherever you got it before.

Touch triggers oxytocin, but anyone close enough to touch you is close enough to kill you. This is why the brain responds to betrayed trust with a huge surge of cortisol, the threat chemical. Neurons connect when cortisol flows, which wires you to feel threatened in similar future circumstances. Thus, we all look for ways to stimulate oxytocin without triggering cortisol. It’s not easy!

4. Serotonin is stimulated by pride.

You may say pride is bad, but you miss out on serotonin when you do. Too much pride can hurt your survival prospects, of course, so our brain evolved to make cautious decisions about when to release it. Serotonin is quickly metabolized, alas, so you always have to do more to get more.

In the state of nature, social dominance promotes reproductive success. Natural selection built a brain that rewards you with the good feeling of serotonin when you assert yourself. A partner who raises your social status triggers lots of serotonin. You may refuse to see this in yourself, though you easily see it in others.

Love is a huge happy-chemical stimulator because it’s hugely relevant to the survival of your genes. You are not consciously thinking about your genes, but you have inherited a brain built by natural selection. Your brain doesn’t give you happy chemicals just for sitting on the couch—unless you are cuddling with someone who could promote your genes. This makes life frustrating for everyone. The more you understand your happy chemicals, the more you can enjoy them in the long run.

Loretta Graziano Breuning, PhD is founder of the Inner Mammal Institute and author of "Habits of a Happy Brain: Retrain your brain to boost your serotonin, dopamine, oxytocin and endorphin levels." Her work has been featured on Forbes, NPR, Psychology Today, and a wide range of podcasts. The Inner Mammal Institute offers free resources that help you build power over your mammalian brain chemistry.  Dr. Breuning’s many books, videos, blogs, and digital resources have helped thousands of people make peace with their inner mammal.