What is Infidelity?

I woke up on Friday morning to find "Blacchyna" trending on Twitter. I rolled my eyes in despair knowing that for some reason the cultural black hole that is Kardashian-Jenner-Kanye-Amber had expanded that little bit more. Oh happy day! It turns out this was just a continuation of hostilities between 'Blac Chyna' and Kylie Jenner over the affections of the rapper 'Tyga'. Happy day indeed! However, it did make me reflect on the nature of infidelity. Why are people unfaithful in relationships? And exactly who is to blame for the infidelity?

Very often infidelity is a straightforward issue of one person stepping out on the other. The person meets another person starts a relationship and it eventually moves from friendly to intimate. It may be a one time thing or it may result in starting a whole other family. However it ends up it amounts to being unfaithful. 

But what happens if the friendship doesn't become intimate? So you throw in the flirting and the impure thoughts but there is no consummation. Does that still count as infidelity? It is possible there may been intent to get intimate but no opportunity presented itself. Or maybe there was just a fantasy of getting intimate but no attempt made to take it further. The person may not consider it cheating but will that person's partner think the same. Is there a 'no sex, no foul' rule? When does deception occur? Is it in the thinking or in the actions?

When two people claim to have an open marriage/relationship in which they agree to allow each other be intimate with other people, where does that figure on the 'infidelity index'? If that is considered okay then it would appear that being intimate outside of a relationship may not be the ultimate test of what is unfaithful. It would appear that if there is pre approval then maybe there is no infidelity. Though I do wonder how things might feel for the third party who might just be a sexual pawn in some couple's non traditional living arrangements. Maybe the other person is the one being cheated on here. After all that person may have very little idea of what they're getting themselves into. That would appear to be open to a claim of deception. 

So this is what I've come up with so far; sex may or may not matter when it comes to infidelity, and if there is agreement by both parties then it may not be cheating (in fact in that case, the person being cheated with may end up being the person being cheated on!). Is it possible that if a person in the a relationship is being totally neglectful and emotionally unavailable then that can be taken as constituting approval to step? Maybe cheating just depends on intent and emotional commitment on the part of the person looking to stray. It can't just be down to what one person or another considers fidelity or infidelity. Or can it?