Simone Holtznagel takes another swipe at her ex Jono Castano as she speaks about their split for the first time: 'You can't change people'

Simone Holtznagel has taken a swipe at her ex-boyfriend Jono Castano as she speaks for the first time on their acrimonious slit. 

The model, 31, who is raising the former couple's baby daughter as a single mother, told Stellar Magazine that she 'couldn't change' the man she thought she loved. 

'I wanted to set an example for my daughter; that's something that shifted for me. One day I was like, "What am I doing? This isn't right." And I would hate if she was ever in this situation,' she said. 

'You have to do what is right for you at the end of the day. No matter the number of promises or anything else that people make, when they show you who they are, believe them. Because you can't change people'.

Simone said she is content raising her baby, Gia, five months, alone, and that she is confident she made the right choice. 

'I've never felt more sure of anything. And I know I can do it by myself. It's unfortunate that I'm mostly having to do it by myself, but I couldn't think of it any other way, really,' she said.

'What I'm doing just feels very right for me. The most important thing to me is that Gia is happy and healthy, and that I'm happy too,' Simone continued.

'Because I firmly believe that if the mother is unhappy, it's hard to have a happy child. And I feel like Gia at this point is a reflection of me, as she's just a very content and happy little bubba.'

Simone and celebrity personal trainer Jono, 33, welcomed Gia on Easter Sunday.

In May, Jono confirmed that he and Simone decided to go their separate ways in May - just nine weeks after the birth of baby Gia.

'Who knows what the future holds, our idea is just to be the best parents for Gia at this stage,' he told Daily Mail Australia in a statement at the time. 

A close friend of the couple then revealed the writing was on the wall for the end of Simone and Jono's relationship for quite some time.

A source told The Daily Telegraph that several friends and family members warned Simone her model lifestyle was not compatible with Jono's fitness influencer career.

The first sign of trouble was when Jono posted pictures of himself on a luxurious holiday in Thailand days after Gia's birth on March 31 without Simone and their baby.

Although many of Jono's followers were quick to gush over the snaps, Simone neither liked or commented on them. 

Speaking to Women's Health, Simone addressed the positives and negatives of doing motherhood 'alone', despite seemingly sharing parenting duties with Jono.

Simone, who has not yet commented on the split, also notably failed to mention Jono in an apparent swipe as she thanked her family and friends for supporting her.

When asked about the aspect of motherhood that surprised her, Simone shared: 'Positive: I can do this alone. Negative: I am doing this alone.

'My family and friends have gone absolutely above and beyond for me, and I am lucky that the negatives feel a lot easier with them by my side.'

Despite the challenges of motherhood, Simone described being a parent to baby Gia as an 'absolute joy' and admitted it has not been as hard as she expected.

'Every day, I tell myself, ''This is the last day she will be this little,'' and that helps me enjoy even the smallest or more difficult moments,' she added. 

Her remarks came in a candid Q&A to promote her new campaign with Nala called Sorry To Offend You, which aims to break the stigma around public breastfeeding.

Jono showed his support for her campaign this week as he appeared to be trying to win back his girlfriend, weeks after publicly confirming their split in July. 

The Acero gym owner left a sentimental comment beneath a post about her promotional on Instagram, showing SImone breastfeeding their daughter Gia.

'This is so good well done nuffle,' he wrote, seemingly using his pet name for her. 

His gushing remark came days after he was seen leaving flowers at the 'postpartum hotel' where Simone was staying at with their newborn Gia in an apparent bid to win her back.

Simone's campaign comes after she had been keeping a low profile following the bombshell news about her split from Jono emerged last month.