Three days later, Swiderski told Harris he was leaving "The Bachelorette" because his boss wanted him back in Chicago. It appeared to be a heartbreaking decision.
"This is one of the hardest things I've ever done," he said on the show.
And yet, according to Johnson, she and Swiderski saw each other the next day, April 16, in Chicago and were photographed at a wedding together the following weekend, April 23.
A week later, Swiderski reportedly told both women he was going to Texas for a business trip, but instead flew back to "The Bachelorette" in Los Angeles, and asked Harris to give him another chance.
"I realize that I made a huge mistake," he told her. "I want another shot."
In the end, Swiderski was the last man standing but Harris did have this to say during the finale: "Ed better not ... disappoint me."
On the "After the Final Rose" special, Harris said that after sending second-place finisher Kiptyn Locke home and rejecting Reid Rosenthal's proposal, she was nervous that Swiderski wouldn't ask her to marry him. But he said he knew earlier in the season during their trip to Spain that he would propose if he made it to the final rose ceremony.
"[My ending] was very, very happy," Harris said. "I thought I was going to pass out" when he proposed.
Locke said, "I don't have any hard feelings."
Harris said, "You never did anything wrong," surprised by how emotional she was seeing him for the first time since the show wrapped up taping.
Rosenthal, who Harris sent home because he didn't express his feelings for her, also appeared on "After the Final Rose" and discussed his surprise return and proposal in the finale.
"I thought she was going to say yes," he said, adding that, "of course," he still loves her. "I'm still upset."
"Was there a part of you that wanted to say yes?" Reid asked Harris. "If I told you how I felt earlier, would it change anything?"
Harris said she was confident she made the right decision, but acknowledged it was difficult to face Reid.
Rosenthal accepted her decision and said "you seem happy."
Harris, who made it to the final three in last season's "Bachelor" with Jason Mesnick, became a fan favorite after her bubbly personality and honest remarks about love and life captured America's heart.
If Harris and Swiderski tie the knot, they would be only the second "Bachelor" or "Bachelorette" couple to make it down the aisle. Trista Rehn, who came in second on the first season of "The Bachelor" and was the original "Bachelorette," married her pick, Ryan Sutter.
Today, they have two children.
ABC News' Lindsay Goldwert and Momo Zhou contributed to this report.