I've been through this one, and it isn't really a whole lot of just leo, but it probably is a bit more common of a scenario. This would be the ego-crushing backlash, I believe. Leos like their friends very much, and once an attatchment is formed it is difficult to break off. He could love both of you, he could simply care for both of you, or he could care for both and love one. Frankly, it's probably not wanting to hurt either of you by telling you he doesn't want to be with you but also not being able to be with both of you. My best advice would be to give him an ultimatum, but try to be friends with him if he chooses the other woman, if it would be emotionally sound for you.