There seems to be trouble in paradise between Cardi B and Offset again -- 'cause they've unfollowed each other on social media ... and wifey's talking about being over relationships.

The married couple appear to have removed the other from their followers' count on Instagram sometime between Monday and Tuesday ... which might sound silly, but undoubtedly carries a lot of significance in the digital age.

More importantly, CB posted a not-so-cryptic message on her Story that seems to touch on some new woes ... alluding to growing past relationships, and putting the focus on herself.

She writes, "I'm tired of protecting peoples feelings...I GOTTA PUT MYSELF FIRST."

Offset, meanwhile, also appears to be referring to problems in their dynamic -- posting a famous clip from "Scarface" where Tony Montana is yelling at his old friend about being the one who put their operation together and being responsible for their success.

There's nothing really beyond that ... but their respective posting is telling in and of itself, although it's unclear what the latest issue between them might be. There's always something.

Remember, it was just earlier this year that Offset suggested Cardi might've cheated on him -- something she denied at the time and which they bickered over for a bit ... that is, until they suddenly kissed and made up, with everything being fine again not too long after that.

Of course, they've historically had lots of other problems in their marriage ... which are always well-documented. They've even broken up before, but on each occasion -- they've gotten back together.

Still, for whatever reason ... this one feels a bit more ominous, especially Cardi's wording here. She and Offset have been together for years now, and it goes without saying ... they have a whole life and even share children.