I am dating two guys and I have to choose between them?

"KC" is a douche. Dump him. You never should have said yes to going exclusive with him if you really weren't 100% about it. Explain what is going on, and then ask him how he feels about it. Tell him that you think that you still care about "RT" and that you are unsure of what to do. If you think you can, talk to them together. Personally, I would go with RT.