Bella Hadid's Ex Adan Banuelos Thought They Were Still In Relationship

Bella Hadid's ex Adan Banuelos was apparently the last to know their relationship was over ... 'cause TMZ has learned the horse trainer was blindsided to learn the supermodel is single.

Sources with direct knowledge tell TMZ ... as far as Adan was concerned, he and Bella were still in a relationship ... and he only learned about their updated relationship status when we dispelled rumors that she was dating her friend's brother, Nathan Lacy.

In our story Monday, we revealed Bella is single ... and our sources say Adan didn't know that was the case until he saw our reporting.

It sounds like Adan had reason to be caught off guard ... according to our sources, the pair had been spending plenty of time together recently.

We're told Bella and Adan recently took a trip together to Aspen, where they went out to dinner several times and attended multiple rodeos ... including one in Snowmass on June 29 and another in Silver City on July 1.

We obtained a photo of them breaking bread on June 29 ... and they were also spotted at Aspen hotspot Kemo Sabe on July 4.

After their time together in Aspen, we're told Adan headed back to Texas for a horse competition while Bella traveled to another Colorado city to visit mutual friends.

Bella and Adan first sparked romance rumors in October 2023 and they had been off and on for over 2 1/2 years.