Ouch! I've dated two WLs. Three long term non WLs. I'm generalising of course when I talk about these things. Are you doubting my, er, experience sunshine?
I will say one thing triggered by someone else's posts on this thread: in once case the WL initiated the relationship where she became a crazed jealous stalker and in another I initiated the relationship and she was open to an open relationship (I don't do open relationships oddly).
Opinions are based on my personal experiences. Yours may vary. Good luck to you.