The billionaire, Travis and Stormi hit up Sweet Chick -- co-owned by Nas -- Thursday night in L.A. It's the first time we've seen the famous unit together since Kylie accused Travis of cheating, triggering an epic blowup. The couple didn't say much as they left the restaurant and piled into a car.

It appears Travis and Kylie were headed to another spot, because Travis loaded Stormi into a different vehicle ... apparently sending his daughter home for beddy-bye as they hit the town.

TMZ broke the story ... Kylie allegedly found evidence last month on Travis' phone that he was unfaithful after the rapper made a surprise visit home. Travis canceled a show in Buffalo in an attempt to calm things down, but if it worked it did so only marginally.

Sources close to the couple told us, while they never officially split over the fight, their relationship was strained ... and they'd need time to figure things out.

As for Kylie and Jordyn ... looks like they're never gonna figure it out.

Glad to see Kylie and Travis back on track.