Starting out in swinging can offer thoughts of insecurity at many junctures on your journey. This is entirely normal.
A key thing in swinging is communication. This is said over and over again to new couples. Absolute, completely open communication. By that I mean being able to talk through your innermost thoughts, desires, fantasies, fears, qualms, jealousies and insecurities. It's important for both of you to be able to do this with each other. Both of you, in listening, need to be non-judgmental, receptive, not sarcastic (even playfully). Being in any sense negative can prevent the walls from coming down between each other. Most couples have walls. It's 'normal' unfortunately. Doing so helps to achieve a much closer sense of intimacy with each other. Is it possible to get into swinging successfully without this? Sure, but it's a lot easier with this. Having such a deep level of communication helps to ease insecurities significantly.
It's true, finding a single female willing to play with you while your husband watches is going to be difficult. Not impossible, but difficult. It's the proverbial unicorn; fabled to exist but never found. That said, couples can and do find such unicorns, but it's uncommon.
There's no particular roadmap, as it were, to get you from where you are to where you want to be. It's a journey the two of you do together, and you chart your own road. You might hit some bumps along the way, but it's bumps that you take together. You're the team.
One rule of thumb that's often mentioned around here; a couple should move only at the speed of the slower of the two. If your husband isn't ready for another man to see you naked, then wait on that. As mentioned in another thread regarding some questions you have, you can get sexually playful and experiment without inviting others to participate.
Another idea; you can go to a swingers club, and just be a spectator. When you feel more comfortable, you can take a room for just the two of you and have sex there. When you're more comfortable, you can let others watch (but not participate). Some clubs have curtains on their rooms that you can open if you want others to watch. Some have doors that you can open, but put a rope across from the handle to the frame. This says "You can watch, but don't come in". Most (all, I've been to) have public areas where you can have sex with each other while anyone can see you. If it's just the two of you having sex, your husband might feel more comfortable with you being naked in front of others.
Another idea; you can go to meet and greets and/or hotel takeovers. This is where a organizing swingers group puts together the event, and lots of swingers come to mingle. There will usually be a non-playing area where like minded individuals can talk with each other. It's a good opportunity to meet swingers in person. That even by itself can reduce some insecurity to understand swingers are really just like anyone else. Also, there's a possibility that if you go to a meet and greet/takeover, you might possibly bump into a couple where they are happy for the wife to go off and do her thing with you two.
Doing these various ideas, while keeping those lines of communication wide open, can slowly bring the confidence of both of you up, as well as your closeness. From what you've posted so far, it sounds like you have a great relationship. Swinging will likely make it even closer. Another saying around here; swinging is a magnifying glass; it increases what it sees. If there's trouble in the relationship, it will magnify that. If there's strong love, it will make it even stronger.
I know you're not even considering the idea of full swapping with another couple, and that's fine. It's also fine if you never do that. There's no competition here :) I just wanted to add that there are many couples that do full swap and have bisexual wives. Maybe somewhere down the road that's a possibility.
It's your road :) Live it!