How should I bring this project to life, keeping in mind that I don't want to be handing my design over to multiple manufacturers, as I'm afraid of having my idea stolen. The metal product will be a small detailed item (no bigger than 3" long) with a removable section (think a sword and its sheath). To be made of titanium. I will first need it drawn in CAD, prototyped, and then manufactured.
That's a common fear, but you are better off putting that aside and just going for it. Instead of worrying about someone taking your idea, have any manufacturer, pattern maker, etc sign an NDA, and move forward with your idea. And most importantly, work with people you can trust. Even if your idea is revolutionary (and I'm sure it's excellent), the people you talk to are most likely busy enough with their own endeavors to copy someone else's project. Not to mention they aren't going to be as passionate about it as you are. I'm happy to help if you need advice or a contract. Good luck and take action!