8:39 AM PT -- Brian Austin Green just posted a cryptic message which seems to squarely relate to Megan and their circumstances ... "Eventually butterflies get bored sitting on a flower for too long. They start feeling smothered. It's a great big world and they want to experience it." Translation -- sounds like he's saying Megan got restless.
The actress was spotted with MGK Friday grabbing some coffee and grub to-go near L.A., then hopping in his whip and leaving together -- presumably back to her place in Calabasas, or so we've been told. They seemed super friendly in the car ... and super caj.
It's just the latest sign that something's probably amiss with Megan and her husband, Brian Austin Green, whom she married in 2010. Meg's recently been seen not wearing her wedding ring ... ditto for him. Reports say they're even living separately during quarantine.
Their relationship has famously been on and off throughout the years -- they once called off their initial engagement before getting back together and finally pulling the trigger. Megan also once filed for divorce a few years back, but they got back together yet again.
Megan and Brian made a red carpet appearance together late last year -- the first time they'd done so in a while. They share three children together ... all of them are young.