But we’re not doomed to see our levels of gratitude and appreciation drop the longer we’re together, as this study found.

The participants were either assigned to a control group, where they were left to their own devices, or to the treatment group, where they participated in one of two relationship education programmes, OurRelationship and ePREP, which both help couples to communicate and deal with problems. It was found that for those in the control group, gratitude levels remained the same throughout the study. But those who received intervention reported feeling more gratitude for and feeling more appreciated by their partner – and other parts of their relationship improved too.

What this suggests is that just like in the realm of mental health, within our relationships we can make the conscious choice to feel more grateful to our partners – and this could be a key component to making a relationship happier and healthier.

Barton’s main bit of advice to couples? Say ‘thank you’… and really mean it.

Why saying ‘thank you’ in a relationship is more important than you might think