But what happens when a child is born? How do you deal with the innocence of infidelity?

For Catriona*, a social worker and mother of three, her husband's three-year affair began 19 years into their relationship and 10 years into their marriage. Her story is one of courage and resilience, an empowering example of one woman's heartbreak ultimately helping hundreds of people.

Catriona's husband travelled often. He began an affair interstate and within a few months was deciding to end it when "she" told him she was pregnant. In the final 12 months of the affair the partner followed his family as they moved interstate.

Six months into the move, Catriona's husband decided to stop seeing the other woman in secret and invited her into their family home. “She'd come over to our house a number of times a week to 'hang out', eat the meals I cooked and get me to look after her child while she worked,” Catriona recalls.

“I told him I didn't like her. I felt as though I was being taken advantage of and could see she was infatuated with him, but he was insistent she'd be welcome in our house, feeding me a sob story about her being lonely."

Her husband's failing plan to merge both worlds had almost broken down when he decided to come clean. Catriona learnt the truth in late August 2008, the week the child of the affair turned two.

“Calmly he said he had something to tell me, dropping the bomb that tore my world apart: 'I had an affair with X, and Y is my son'. My brain tried to compute the information but my body was already reacting, grabbing the bookcase and hurling it across the lounge room, screaming 'NO',” Catriona says.

Six years on, she and her husband have rebuilt their marriage, which is better than ever, and Catriona has opened her home and family to the child. “This wouldn't have happened without my husband consciously working for more than two years, willing and committed to do everything he could to put all the wrongs to right,” she says.

With nearly 20 years' experience as a social worker, Catriona began a counselling and support service dedicated to helping couples locally and internationally who are struggling to recover from an affair.

“If finding out about your partner's affair is one of the most devastating events in your life, discovering a child was or will be born of the affair comes a close second,” Catriona says.

While the damage of an affair can take years to repair, a child born of an affair is a permanent consequence.

“They're a little person with the same right as all of us to feel safe, loved and secure in the world they've innocently been brought into,” Catriona says.

Once it has been confirmed that the child belongs to your spouse, balancing their rights and needs while healing the relationship is a task that requires objectivity at a time when emotions are running high. Catriona offers some helpful tips on how to begin the long road to recovery:

Work on the relationship first

This is crucial. As your relationship strengthens, your ability will increase to work as a team through the issues regarding the child. Remember that it takes time and there are no quick fixes.

Set clear boundaries

Boundaries keep a marriage safe. All relations with the affair partner must end. Any communication relating to the child should be transparent, traceable and planned. For example, through SMS and email. The affair partner and offending spouse should never spend time alone.

Know your rights

Research family law that is relevant to extramarital children in your area and understand your obligations.

Other children

Parents must present a united front and tell their children about the situation in an age-appropriate way. Children need to feel comfortable that they can talk about it, so be prepared to answer their questions and DO NOT tell them to keep it a secret.

Seek professional help

Many people who find themselves in this situation suffer in silence and shame. If you can't tell friends or family, see your GP or seek out counselling services in your area for help and advice.

*Last names have been withheld to protect the identity of the minors involved.