The pair have lived in Swinger Hill for 21 years and next year they celebrate their 30th anniversary.

The couple agree with clinical psychologist Amanda Gordon's top five tips for a healthy marriage or relationship. And each month when things get busy they go out for dinner to reconnect and talk.

Describing their attraction as ''pretty instant'', they aren't certain why civil unions seem to last longer than traditional marriages. ''It is possible that this type of union lasts because it has been so long in coming; people who use it are ones who have had time to think,'' Ms Healy said.

But when it comes to their relationship, they ascribe its longevity to love.

''We love each other but also we had a bit of experience; we were both well into our 30s when we came together so we knew what we wanted and what we didn't want,'' she said.

Ms Nicholls said knowing what you wanted and did not want were equally important.

''What surprises me is how people stop listening to each other in relationships,'' she said. ''You really need to listen to each other.''

She said making their partnership equal was a priority.

''Neither is dominant or submissive and we've worked quite hard on that… that includes things like money because Christine has always been a higher earner than I, but we've named the problem and talked about it … I earn less but I'm not going to be the housekeeper.''

■ Appreciate each other.

■ Find things to be grateful for within the relationship every single day and share that with your partner.

■ Look for ways to make the other person's life better.

■ Never go to sleep on an argument - sort it out.

■ Talk about it - whatever it is - talk about it.