Absolutely you have been cheated on. Even if it wasn't physical (unlikely), you're husband lost feelings for you over this thing.
He bad-mouthed you to this woman and was fantasizing about leaving you for her.
What he was doing wasn't as bad as sex, but the emotions involved were just as destructive as sex.
What you are feeling is perfectly normal. What you feel as a result of what he's done, and what he doesn't feel, is all HIS fault.
Whatever you decide about your marriage is more than justified, even if you left.
Just out of curiosity (and to strengthen my own arguments should I ever need to use them, lol), what if he had been communicating his feelings and getting support from a close male friend he had made? If he shared with him that he was fantasizing about leaving his wife, whether for another woman or just to be on his own, and his friend was supportive of the idea or encouraged him to do so? Clearly, it is miserable thinking about your spouse is talking this way about your marriage and you to an attractive member of the opposite sex, but he can make the case that he wasn't 'cheating' as he *could* have behaved in a similar fashion with someone who was *not* attractive. Her being attractive doesn't make what he did 'cheating.'
Again, I'm playing devil's advocate here - I can certainly appreciate how ****ty she feels about what he did. I'm just trying to unpack the 'but I didn't cheat' defense...