I don’t think the signs have much to do with anything. It’s difficult to give advice if we aren’t offered the backstory or at least part of the information. For example, why did you break up? What was your relationship like? What is he like and what are you like? People aren’t defined by their astrological signs, and thus, there is no one answer to how to fix things like this.
Why did you break up with each other to begin with? Is he really that good of a person? You can look up and research the things that attract leo's such as activities, personality to try and get back together with him. OR you can try and find other leos that you may be attracted to.