I guess it's EWWWWW if W isn't attracted to him but HMMMMMM if she is.
I think boss and W would say they just have different opinions about what is friendly vs. what is inappropriate. (of course they would!) If he has W going along and happy about this, then they can hide under the "just friends and coworkers" label for awhile.
Would you believe the story gets more complicated? Boss' W starting working here PT this month. Gosh, I wish I knew what SHE thinks about all this.