A writer met up with her ex-husband like Carrie Bradshaw and Aidan — and it was a total car crash. A therapist shares 5 lessons to learn.

• A writer met up with her ex-husband after 15 years to find out if they still had chemistry.
• She was inspired by Carrie Bradshaw and Aidan reuniting in "And Just Like That."

Viewers are yet to see what will happen when Carrie and Aidan reunite in "And Just Like That," but meeting for the first time in 15 years was a total car crash for one married couple inspired by the characters.

Liz Jones, 64, a British columnist, and her ex Nirpal Dhaliwal, 49, also a British journalist, met in 2000, married two years later, and finally divorced in 2007.

In a viral article published by British newspaper The Daily Mail, they both detailed their perspectives on the meet up, with Jones writing that Dhaliwal had "zero self-awareness. No filter. He doesn't take the blame for anything."

She claimed that he cheated on her multiple times and described their wedding day as "awful."

Dhaliwal said he was "thoroughly glad to be rid of her" and "mortified at being photographed with her." He was also angry about her "[spitting] venom" about him and their relationship in her writing "for 16 years."

The article sparked a major reaction on social media, with many shocked by how explosive it was, and the way Nirpal spoke about his ex-wife.

"With every line I thought, this is awful maybe the worst thing I've ever read nothing will ever top it, and then I read the next line and it was worse, it really builds," one journalist tweeted about the article.

Insider spoke to Deborah Krevalin, a relationship expert and psychotherapist based in Connecticut, about the lessons to learn from their encounter.

Don't rush into a relationship before you really know each other

Before rushing into a relationship or marriage, it's important to really get to know the other person, Krevalin said.

"Many fall in love with falling in love, and of course we do, because it feels so good," she said, explaining that our brains release the neurotransmitter dopamine during this process, making us feel euphoric. But we can end up infatuated with someone before we actually know if they are a good fit for us or shared enough experiences to know how they handle difficult or stressful situations, she said.

Krevalin recommended consciously slowing down and checking in with yourself before making any decisions.

"We need to be responsible for our decisions, which means we need to put more care into the decisions that we make, whether they're financial decisions, familial decisions or relational decisions, we need to slow down," she said.

Being lonely is better than being in the wrong relationship

If we are with someone for the wrong reasons, such as settling or societal pressures to be married or have children by a certain age, we are unlikely to get what we want, Krevalin said.

People get married for a variety of reasons, she said: Someone who grew up without enough food on the table may look for financial security, while someone else might value status and want to attach themselves to a high-profile individual.

"People can feel desperate at times or they can feel pressure, and that can really get us off track from our true value system around love, marriage, and partnership," she said. "Sometimes choosing to be lonely for a while is a better option, even if it feels uncomfortable."

Use the same relationship playbook

Attraction alone is not enough to make a relationship work. You need to make sure you are using the same relationship playbook, Krevalin said, including agreeing on what you both want the relationship to be like and your expectations of each other.

Making intentional agreements, such as promising to go on a date once a week to spend quality time together, is another really important factor in healthy relationships, according to Krevalin.

"That way you can both be contributors in writing your own love bible," she said.

You can always change your mind

A particularly shocking moment in the article was when Jones wrote that she "knew it was a mistake, but it was done" the day after her wedding.

"But it didn't have to be done!" Krevalin said.

We have all made a hasty decision and regretted it but felt trapped by a fear of judgment from others or our own inner critic, but it's never too late to change your mind about anything, she said.

"Sometimes we just make a mistake and we all deserve a second shot at rectifying a bad decision," she said. "It's a tough situation and hard to back away, but it is possible."

Don't meet up with an ex if it ended badly

In terms of having any kind of relationship with an ex, every situation is different, Krevalin said.

If things ended on a positive note, for example you broke things off because someone took a job abroad or you just weren't right for each other, it is definitely possible to reunite later in life on good terms, she said.

But if the relationship had negative, or worse, abusive elements, "it's a hard no" on reuniting from Krevalin.

"If you've experienced a relationship where there have been some real red flags or unhealthy behaviors, don't dip your toe back in that water. There are so many other people out there to get to know and enjoy," she said.