"I realized that when I was away from Des, I wasn't having these moments of anguish," he tells PEOPLE. "That was a big indicator to me that my feelings weren't there."
He says: "I wanted so badly for [the relationship] to work out, and it was so close I could almost touch it. But I needed to walk away. She deserved to be in love with someone who was equally in love with her."
Buzz abounded that the handsome former model would return, but, for his part, Forester says, "I made the right decision."
He adds, "It was hard and there were things I missed about Desiree right away. But I knew long term that it was right."
After their reunion at Monday's After the Final Rose taping, Forester gushed about the happy and newly betrothed couple. "During filming, I could see the way Des looked at Chris," he says. "Des came with the objective of finding love and so did Chris and they found that. I tip my hat to them."
Now, the 28-year-old sales rep is single and ready to dive back into the dating world. "I'm excited to begin the search again. I'll never give up on love. It's what I'm looking for, part of the pursuit of happiness."
For more on Desiree, Chris and The Bachelorette's dramatic season, pick up the new issue of PEOPLE, on newsstands Friday