You don't have to dump a cheating partner.

I always thought I was the kind of person who’d leave if my partner ever cheated on me. I thought I’d pack my bags, jump in the car, drive off and never look back.

But I loved him. That’s why it hurt so much. I was in love and I really and truly believed he loved me too. So why did he cheat on me? Why did he hurt me so badly when we felt so lucky to have even found each other?

And was I willing to walk away from the best relationship I’d ever been in just because of one, meaningless affair?

Yes I yelled, screamed, sobbed and threw things but I still didn’t leave my partner after he confessed to an affair, partly because I loved him and partly because I didn’t want to leave until I fully understood why it had happened.

Affairs affect one of every 2.7 couples, according to counselor Janis Abrahms Spring, author of After the Affair, with approximately 10 percent of those lasting less than a month, 50 percent lasting more than a month but less than a year and 40 percent lasting two years or more. A lesser known fact is that the person having an affair rarely ends up with the person they were cheating with.

So why the hell do so many people cheat?

Mamamia Confessions: Relationship deal-breakers. Article continues after this video.

Dan Auerbach, Director and Relationship Counsellor at Associated Relationship & Marriage Counsellors Sydney says affairs usually happen when someones needs aren’t being met in their relationship.

“The method of counselling that I work from is an emotionally focused therapy for couples and it really helps people to learn about their attachment needs and how to represent them safely and how to reach and respond. And it’s a universal human need. If we don’t have it with person A we’re gonna have to find it with person B because it’s not going away.”

Auerbach also believes having an affair isn’t a real solution for people trying to get their needs met.

“So there’s a need to partner up, and if we partner with many different people it’s sort of a consumerist supermarket orientation to try and get attachment needs met.”

Straight away after Auerbach said this I started trying to examine my past experience, trying to figure out what need my partner wasn’t having met by me and what I could have done to prevent the affair that he had, but I was quickly corrected. It’s not about blame. It wasn’t anything that I did or didn’t do. How could it be when I didn’t know what I wasn’t doing? And how could my partner verbalise a need he wasn’t properly aware of?

When in our lives are we properly taught about how to have a healthy relationship? Movies and books and watching couples around us is not how to properly teach people how to have a lasting relationship that fulfills each person's needs.

If only we all accessed couple's counselling much earlier, before our relationships hit crisis points like affairs.

"For the person grappling with their partner's infidelity, the experience is often (not always) akin to a post-traumatic reaction, with the foundations of the world as they knew it shaken to the core," says Clinical Psychologist Lissa Johnson. "It’s important for the partner who had the affair to realise this, and to be patient and understanding with their partner’s recovery from the trauma. The trick in this process is not falling into a trap where one person is the victim and the other is the offender."

I remember my partner doing this for years. Determined to repair our relationship, he took all the blows I delivered to him, for just over a year, until one day during a completely unrelated argument over something insignificant I once again, for the millionth time brought up the subject of his affair.

He said, "When are you going to stop using that as your Get Out Of Jail Free card?"

"Um, never," was my first thought, but his comment made me realise that it wasn't enough to stay together. I had to forgive, we had to repair, and we both had to move on. But how to do this when the mere thought of him being intimate with someone else left me feeling physically sick.

"The more that you are sensitive to what your partner needs in order to heal, the more willing your partner will be to try to understand you, your experience of the infidelity, and your unmet needs," continues Johnsons, who also explains that talking about the affair and unmet needs isn't about blame. Instead she says it's about you both collaborating as a team to understand your relationship dynamic better, a dynamic you are both responsible for.

"Work on taking responsibility for your part in any destructive dynamics, which will help your partner to take responsibility for theirs. For example, your partner can’t truly support you emotionally if you don’t share how you feel."

That means that when my partner comments on how little time we spend together, how often I cut him off or how rare it is for us to spend quality time together, I have to choose to listen, just as he has to listen when I say that he has to stop leaving it to me to find the quality time. He has to get off his butt and organise stuff too.

My partner and I have now been together for 18 years. Our relationship isn't my responsibility, nor is it his. It is ours, together.