The pair were seen holding hands and packing on the PDA as they left a gym and took in a spot of shopping, including a visit to a Sephora.
The mystery man even took his top off for part of the excursion with Monique barely able to keep her hands off him.
An eyewitness said: "It looks like they've known each other for a long time with the way they were carrying on and touching each other."
Monique has also been linked in the past to Married At First Sight star Jessika Power's controversial brother, Rhyce.
It is believed they were together in their early twenties, but split "when Rhyce moved away for work and Monique started travelling".
The former Perth lingerie designer ruffled a few feathers when she made a dramatic entrance as an intruder last week but she was not impressed by the behaviour of the other women.
“It’s interesting to see what the girls were saying behind my back because obviously in the house, and just chicks in general, they aren’t ones for confrontation,” she told PerthNow.
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“There was a lot of ‘We love you, we love you’ but really there was a lot of cattiness and bitchiness ... I think it comes from a place of insecurity, to be completely honest with you.
“I also think it’s somewhat of a culture in Australia, unfortunately. Australian women just tear each other down to get to the top and it’s really sad.
“We have to recognise that everyone is an individual and we don’t have to compare ourselves. Especially with Instagram removing the likes, it is encouraging us not to do that any more.”
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