Last month, the duo were crowned as the winners of the ITV2 dating show.
Fans are worried after Mimii's latest social media updates show her partying without Josh.
She was snapped with fellow co-star Omar Nyame, who was a bombshell arrival in the latest series.
In a short video posted to Omar's Instagram story, the pair are seen smiling and posing for the camera.
Earlier this week, fans shared their concerns over the romance in Mimii's comments section.
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One wrote: "Are u N Josh still together", under a post from earlier this week.
Another added: "[Josh] is nowhere to be seen lads so I don't think Mrs anything is in order."
However, a fellow follower refuted this, as they replied: "You can see he was there from the videos on my page so just relax a bit."
It comes following concerns when Mimii was absent from one of Josh's nights out.
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He attended Love Island stars Indiyah Polack and Dami Hope's event to celebrate their latest collaboration with Gym Shark.
Josh was all smiles as he danced the night away with his girl's ex Ayo Odukoya.
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In another clip, uploaded by Ayo, the pair posed for a video with Dami while hanging out at the venue.
Meanwhile, Casa Amor bombshell Diamante Laiva had her say on the romance - insisting they're just private people.
Speaking exclusively to The Sun, she said: "I met Mimii at the reunion for the first time.
"Obviously, at the recoupling I didn’t get a chance to speak [to her] because her situation was crazy. Mimii is so… her soul is so pure. I can’t even describe Mimii, she’s so nice.
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"I met Josh very briefly so I don’t really have an opinion on him.
Diamante added: "Love Island puts your relationships on display. I think, where’s she’s Christian and very spiritual, she likes keeping things private.
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"She did mention to me that they’re [taking things] slow, no pressure and I think they just want to do things privately."
Love Island airs on ITV2.
