Kluth said he and the former Real Housewives of New York City star ended their engagement several months ago.
"After fourteen months of engagement, Tinsley and I have ended our relationship, and we have been living independently for the last few months," the CouponCabin CEO said. "This was an incredibly difficult decision, but it is one that I believe is best for both of us. I will always care about Tinsley and I sincerely wish her happiness and success in all that she does in the future.
"While I understand this news will be of interest to many, I ask for privacy and understanding during this time as I continue to work on recovering emotionally from the end of our relationship."
However, the split was allegedly not a mutual decision; the reality star reportedly felt "blindsided."
"She's on the floor heartbroken and devastated. She left everything for him because she didn't think he'd ever call off the engagement," an insider said. "She trusted him that this time was going to be different."
Last year, the 45-year-old even left RHONY to move to Chicago to be with Kluth after they met on a blind date in 2017, which was set up by RHONY costar Carole Radziwill.
"With Scott, so much has happened so fast," Mortimer said at the time. "I know that if I don't take this moment right now, I will regret it for the rest of my life. I have to listen to myself and what I want and nobody else.
"It's been a great ride and I'm just so happy for where I am right now and for my future."
However, one of the blonde beauty’s pals told Page Six, "He tortured her. For years he would break up with her and get back together with her and break up with her again. But when he proposed, she believed he meant it. She left her career, she left her livelihood, she left her home, and suddenly he’s back to his old tricks again and he called off the engagement."
Added the friend, "He has a fear of commitment. He never had it in him to follow through with his promise to marry her. And he used her celebrity to promote his coupon company."
Meanwhile, Kluth remembers the split very differently. "It is disappointing that during this emotional time for both of them, Tinsley is mischaracterizing the circumstances of their breakup, which happened months ago. As Scott has already said, he wishes nothing but the best for Tinsley and is seeking to recover emotionally and move on," a spokesperson for Kluth said.
While Mortimer did not post a statement of her own, she has interacted with others sharing their support.
"Love you beyond. You’re a dear true friend," she commented on Leah McSweeney’s Instagram post, which was said to be originally captioned "#MenAreTrash."
"Mood. Had To delete my trash # Because people are trying to have this post removed for hate speech. LOL. Proving my # is very true," McSweeney later recaptioned the post.
Tinsley also reposted support from her fans onto her Instagram Story.
PEOPLE was the first to report on the split.