"The best relationship advice my divorced dad ever gave me is also the most surprising."

My favourite nights spent with my dad almost all look the same.

We’re seated outside on the porch, he’s puffing on a Dunhill Light, chasing each drag with a gulp of the scotch he’s been swirling in his hands.

I’m seated cross-legged on a bench, too busy to care about his lungs or his liver. I’m too busy because I’m listening to him grapple with life’s big questions, his nose sometimes flaring with excitement.

“Does God exist?” “Do we exercise free will or are we slaves to our genes?” “What is time, really?”

Inevitably, the conversation turns to relationships. The trials of monogamy.

My parents were heading towards divorce for a long time – since at least my early teenage years, but probably even earlier.

It just took them a long time to realise it, and to eventually come to the difficult conclusion that the best way forward was to cleave our little family-of-five in half.

That was eight years ago. They are only just going through official divorce proceedings now.

The slow-burning divorce gave both my parents time to reflect on what went wrong, which then morphs into advice I'm asked to apply to my own relationship. (Almost always late at night, after a lot of wine.)

But there's one particular nugget I've never been able to forget, and it came first from my dad.

Always look after your own happiness.

Yes. It's probably the least romantic relationship advice you'll ever hear. But it's crucial.

It's about each of you having your own interests. It's about self-care. It's about independence. It's about individual growth. It's about not relying wholly on one person to come home and bring your life joy, because in the long run, that can be a burden too heavy for someone to bear.

Your partner is the person you will spend most of your time with. You wake up together, you eat dinner together, you spend weekends together. And even when you're not physically side-by-side, you're probably exchanging the odd texts, or tagging each other in 'hey-I'm-thinking-of-you' memes on Facebook.

Of course, this constant contact brings you happiness. But it can also become suffocating.

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You need to remember and nurture all things that make you smile outside of your relationship - anything from your career to just about any hobby or a favourite pastime.

Feed your own sense of fulfillment. In turn, give your partner some brief space to miss you and another reason to be proud of you.

And if things do go terribly awry, it'll be hard. But wouldn't it be so much harder if you didn't have self-satisfaction in other areas of your life?

Always look after your own happiness.

I've carried these six words with me for a long time. My mother has since said similarly wise words: Don't let anybody affect your happiness. And over time, I've seen articles in which marriage counsellors give the exact same advice. (See: Have some "me time".)

The thing with divorced parents is they've seen the good, the bad and the ugly of marriage. They're in a prime position to learn from their mistakes.

And almost every child of divorcees I know has got some form of key advice that has stuck with them.

For one friend, Kathy*, her father's advice centres on communication.

"Communicating was my parents' main downfall. If you have something on your mind, talk about it straight away. Don't let it brew because it'll just turn into a problem or an unnecessary fight."

Another, Jess, says her mother advises her to keep going to bed at the same time as her partner.

Liam's advice from his mum echoes that of my own father's: "You've got to please yourself." And she backs his decisions as long as he is happy with them.

Lily's mum had a solid warning for her daughter: "A problem that's bad in dating is made 10,000 times worse in marriage."

Danielle is told by her mum to remember that no, opposites don't attract. Having similar interests is important.

What relationship advice did your parents pass onto you? Tell us in the comments below.

*Names have been changed.