"My husband started getting obsessed with a mum at school, then I found the messages on his phone."

What do you do if you find your partner has been sexting someone else? Do you end the relationship? Or do you have a better chance of working through things, because it’s just sext, not sex?

This is the dilemma that’s facing a mum who’s discovered that her husband has been sexting another mum at their kids’ school.

The Mumsnet user says her husband is a “great” man who’s always been supportive of her, and is also good with the kids and with housework. But she’s discovered a series of messages between him and another woman.

It seems her husband noticed the woman at school and began “obsessing” over her.

“Of what I can tell from their messages (there were too many of them), he’s the one who pursued her and she didn’t put up any resistance,” she wrote. “I read how he called her ‘possibly the most beautiful human being on earth’, for instance. At some point they started sexting, explicit messages telling her what he wanted to do to her and a photo of his erection.

“As far as I can tell, they actually haven’t slept together but it seems like they both want/plan to. I don’t know how to move forward from this. One part of me says it isn’t cheating – “nothing” has happened – but it’s not just the sexual content that upsets me. I’m so heartbroken he’s so infatuated by her and that he actually pursued her. I never thought he was that type of man.”

Hundreds of women replied, most of them telling her she should immediately end the relationship.

“You need to build yourself up and kick him out,” one wrote. “He clearly has no respect for you at all. He is not the great man you describe him to be. How do you know he hasn’t done this in the past with other women?”

Another said she’d been through a similar experience.

“My ex-husband had an emotional affair (this is exactly what your husband is doing), and we simply couldn't get past it. We tried for a further three years but my respect, love and trust was shattered after reading his messages.”

Dr Karen Phillip, a counselling psychotherapist from the NSW Central Coast, has seen plenty of couples where one partner has been sexting someone else and the other partner has discovered the messages.

“For most people, particularly women, it is absolutely a form of infidelity,” she tells Mamamia.

“I’ve had a number of couples where she’s found out and he’s going, ‘Yeah, but we didn’t do anything,’ and I say, ‘In fact, you have done something, you’ve upset and distressed your wife, you’ve shared part of your emotions and perhaps pictures of your body and so on with another woman.’ So yes, it is, in fact a form of cheating.”

Interestingly, out of the couples in this situation that Dr Phillip sees, about 60 to 70 per cent end up staying together, as long as there’s no history of abuse or infidelity in the past.

LISTEN: Psychologist, Esther Perel knows why happy people cheat (post continues after audio..)

She says if the partner who discovers the sexting has been happy up until then, and they feel like they’ve got a good relationship and a good partner, then they need to uncover the reason why this has happened, and whether there are issues in the relationship that need to be addressed.

“Most of the time, couples can’t really explain or express to each other how they’re feeling,” she believes.

Dr Phillip says couples are less likely to be able to recover if the partner sending the messages has become emotionally attached to the other person, writing things like, “Oh, I love you and my wife doesn’t get me and she’s a bitch.”

“When they start to develop an emotional attachment, the relationship between the husband and the wife usually starts to diminish,” she adds.

Dr Phillip’s advice to anyone discovering that their partner has been sexting someone else is to sit down and try to ask them about it without judgement, “which is very difficult”. That is, of course, if the person loves their partner and wants the relationship to continue.

“It may be a great key to the door that you want to get out of,” she adds.