The couple announced on Friday (March 29) in a joint statement that they have chosen to end their relationship after three years together.
Molzahn and Locke told People: "With love and respect, we decided to take a break in January. We are both focused on philanthropic and personal growth at this time, wishing each other the best.
"Thank you for respecting our privacy... Thank you for your support always."
Locke and Molzahn began dating while starring on ABC's summer series Bachelor Pad in 2010.
Molzahn hinted in late 2010 that she and Locke would likely marry, but the two never tied the knot.
She was previously married to Ryan Natividad. Their marriage ended in divorce in 2009.