"She said YES!! Thanks for making me the happiest man in the world and I can't wait for what our future holds," Ivan captioned a slideshow of photos with his new fiancee.
In the photos, Tailour showed off her four-carat oval engagement ring, and Ivan, 31, also apparently gifted the anesthesiologist a white 2023 Tesla Model Y performance vehicle with a big red bow on it.
Congratulatory messages poured in from Bachelor Nation.
"AHHHHHHH so happy for y'all," wrote Madison Prewett. "Freaking out, so happy."
The aeronautical engineer, who currently lives in Dallas with Tailour, shared, "When she happened to move to Dallas after medical school to work as an anesthesiologist, it felt like we were destined to be together."
"I realized that she was not only my best friend, but also the person who made me feel happiest and most fulfilled in life," Ivan continued. "She supported me through the good times and the bad, and I knew that I wanted to spend the rest of my life with her."
Ivan apparently decided he was going to marry Tailour in late 2022, and then he worked with a jeweler to create her ring.
"I knew what style she liked from all of the DMs she would send me on Instagram," Ivan joked of his bride-to-be's not-so-subtle hints.
When planning the proposal, Ivan recalled wanting the experience to be "personalized and meaningful" to Tailour, which is why he bought her a new car to replace her old college car.
"Our families helped me organize everything and I hired the best Dallas wedding photographer... to capture the moment," Ivan said.
Ivan also hired Susie to work as the videographer for his marriage proposal.
As far as the wedding planning goes, Ivan said he and his future wife plan to "start soon."
"We're both excited to start thinking about the details," Ivan explained. "We haven't finalized anything yet, but we both have some ideas in mind for the location, theme and overall vibe of the wedding. We just can't wait to celebrate our love with our friends and family!"
After competing for Tayshia Adams on The Bachelorette's sixteenth season in 2020 and then looking for love on Bachelor in Paradise's seventh season in 2021, Ivan found The One outside of Bachelor Nation.
"I do have a girlfriend and so I cannot come back to Paradise this year," Ivan told Us in June 2022, right around the same time Bachelor in Paradise had begun filming its eighth edition.
Ivan said he and his girlfriend "actually go way back" because they met each other in college, although they went to different schools.
They apparently met during a winter night out in Austin when Ivan was attending Texas Tech. Tailour, meanwhile, went to the University of Texas.
"We dated a little bit, then spent some time apart. She went to med school. I moved to Florida for an engineering job and stuff like that," Ivan explained.
"And then we reconnected in Fall of last year. She got her first residency [job in Dallas]."
Ivan predicted at the time he and Tailour could work out long-term because they're "a very good match" and she's "an amazing catch."
"I've known her for forever and she's a good person. So I'm very happy that we're together now and being able to be together," Ivan said at the time.
Tailour even watched Ivan date Tayshia on The Bachelorette. She didn't, however, tune into his season of Paradise, when he briefly dated Kendall Long.
Ivan received a sweet and reserved-guy edit on The Bachelorette, but he became a controversial character on Bachelor in Paradise.
Ivan was given the boot from Bachelor in Paradise because he had snuck into The Bachelor alum Alexa Caves' hotel room off-camera during a one-night tropical storm evacuation.
Alexa had yet to walk on the Paradise beach and officially join the show.
Although producers ordered the bachelors and bachelorettes to stay in their respective rooms, Ivan said he stumbled across a list of cast room numbers on a producer's phone that had accidentally been left in the room he shared with Noah Erb.