I don't know the whole situation, but most likely she brought something up that he is getting left out of or maybe he made a mistake of some sort and she keeps bringing it up. If he wanted to go to another country and couldn't because he didn't have enough money and she told him, "haha you don't get to go to Europe" then that would be "rubbing it in his face".

Hi, Dwayne is right in the sense that it means that the man was jealous of her trip and this is an idiomatic expression meaning just that.

Hi:) The expression that you want explained is an American expression that is used as sarcasm:) Sarcasm is saying remarks that are intended to mean the opposite but is used to mock someone:) For example if you are sitting down eating cereal and someone comes to you and asks you "Are you eating cereal?" and you reply "No I'm eating chicken",you would be using sarcasm:) Since the woman said "Wow, why don't you rub that in my face, why don't ya" she meant that as sarcasm and the fact whatever the man said, he was bragging and she didn't approve of it:)