Cimmie - I feel for you situation - it is horrible to go through but to deal with flaunting it afterwards has to be just earth shattering. But Jadedstar is right - regardless of whatever the situation, it is not your fault. You are only responsible for your actions and regardless of your actions (I don't know the full situation) he is purely responsible for his horrible act.
Jadedstar - I do agree that things like lying or omitting that one spent extra money really doesn't qualify as "cheating" in the sense that we are talking about (although by the literal definition of "Cheat", it would be). I am, however, somewhat struggling with the second situation you provided with the female friend. Your justification on lying (or just omitting information) is that if someone sets up unrealistic parameters they are justified on ignoring and hiding the action if they break them. My opinion is that this could end up pretty much negating anything - by that logic, if someone thinks it is perfectly fine to get a lap dance but their partner disagrees, they could declare it an unrealistic parameter and feel justified just doing it anyways. What if someone thinks casual sex isn't cheating? I think it is a very slippery slope. Now I can understand how people can be paranoid and set some insane parameters (myself being one whom has) and it being "easier" to just lie about it, but I think this lying will just fuel their paranoia all the more. I would think the proper way to handle this is just to state "I will be talking to this friend" and not hide the fact. It is then up to the other partner to either accept the change in parameters in their relationship or not. Not giving the partner the opportunity to reject this change in boundaries is cheating, IMHO, regardless of how unrealistic the initial boundary is.
I am still pondering the fine line between "Intimate Friendship" and "Emotional Affair" - does anyone have any thoughts on where that line gets crossed? In my situation, there are the definite things (strong declarations of love and not loving the partner, desire to run away with the friend, indication of wanting a sexual relationship, etc.) - however I am struggling to set up boundaries for the more subtitle things. Another hole in the premise of "what you would do in front of your partner" I am discovering is about sharing emotions. If one partner is willing/able to share their emotions with their partner, but instead chooses to share them with someone else instead, would this be cheating? What about raw time in a platonic manner? Say a partner spends 40 hours a week with some other person thus only has 14 left to provide to their spouse, would this be considered cheating?