Soules and Bischoff got engaged on The Bachelor's nineteenth season seven months ago although the finale just aired about three months ago in March. They announced their split in late May.
"They didn't get to know each other well," a source told Us Weekly in its June 15 issue.
After the proposal was shared with the world on ABC's March 9 broadcast, Soules immediately began 12-hour rehearsals every day with his pro partner Witney Carson for Dancing with the Stars' twentieth season. Meanwhile, Bischoff was working in Chicago about 1,800 miles away.
The 29-year-old fertility nurse visited Soules, 33, but "Dancing with the Stars hurt the relationship," said an insider. "She shared him with other women on The Bachelor, then had to share him again. It bothered her."
In addition, the couple was apparently lacking chemistry.
Bischoff is "sad but knows it was the right decision," the source told Us.
The Bachelor pair released a joint statement to the media last month revealing they had decided to call off their engagement.
"Whitney Bischoff and Chris Soules have mutually and amicably decided to end their engagement," the statement read. "They part with nothing but respect and admiration for one another and will continue to be supportive friends. They wish to thank everyone who has supported them through this journey."