Actually, I think you're doing quite well as far as being poly is concerned.
You took your time in developing the feelings towards your friend, and you discussed things with your husband. A suggestion though. You said that you're not sure this is how you want to live your life. Who said you needed to make that decision? One thing I've learned is that life has no script.
My wife and I NEVER thought we'd end up with a live in gf for the passed 2 years, but that's kinda how things happened. We started by having 3somes, then over the years we talked about things as they happened. Hell, I didn't even realize there was a label for people like us until a few years ago!!
Live your life as you see fit for you and your husband. Make sure that the core relationship you and hubby have is strong and built on the right foundations, such as trust and communication. Keep very open lines and TALK TALK TALK, even if the conversations aren't always pleasant, they are necessary. (You'll see this is a common thread of mine) If you talk about what's going on inside, the rest seems to just fall into place.
Good luck and please keep us posted!