During the experiment, couples answered questions about their interpersonal specific experiences (for example, conflict, conversation, and sex), global relationship satisfaction, and the amount of sleep they got each night.

Scientists quickly discovered that the more shut-eye everyone got, the happier they were in their relationships.

Why? Well, we all need self-control, or self-regulatory strength, to help us differentiate between the daily ups and downs of life and how satisfied we are in our relationships.

Sleep can give us the mental strength to override feelings of despair after a heavy argument, which will help us isolate the event rather than seeing it as symptomatic of a romantic device.

And as self-regulatory strength is affected by sleep, our ability to judge these events without relating them to our relationship can take a significant toll on us and our partners.

So how does coffee enter this equation?

Science says coffee has an amazing effect on your relationships