I don't see what the issue is here. You seem to be trying to be everything to everyone and are forgetting to be everything to you first. You said yourself you want to experience dating... so date. Nothing poly about dating a bunch of women other than you might decide to only date poly women and you should always be up front to everyone that you consider yourself poly.
Now is the time to enjoy getting to know other people and take it easy, not be so serious unless you really like someone. You seem to be creating the drama by being Mr. Pleaser.
As for girlfriend with the husband that doesn't know. If you really love her then request that you meet him before continuing onward so as to keep you integrity and self respect. Also to keep your respect for her. If she says no, then leave her. Full stop, end of story, nothing left to say. There should never be any room for cheating in poly as far as I am concerned. I don't care how "poor me" her life is, there is always the option to leave if it isn't working for her. I have never heard one excuse yet that has made me say, "ahhhhh, that's too bad, you should keep cheating..." sorry, I'm a bit of a hard ass on that one.
Btw, there is tons on cheating on this forum, it might be helpful to do a search and read up a bit.
Anyone want to be friends on Facebook?
Send me your name via PM