Well Ariane, I would ask you to consider this...perhaps that (sex is the reason) is what most men say for a couple of reasons.
First, they are there to have sex.
Second, many men are not able to either connect with the real reason; admit the real reason or do not understand the real reason therefor they say it is sex.
It is no secret that we men often have a hard time being in touch with our feelings.
You are absolutely right.
But I think it's true in most cases: when you ask someone the reasons behind their choices, only a few will give you a well-thought, truthful and deep answer. People don't bother analyzing who they are. Which I think is unfortunate because if they did, there would be more decency and kindness in this world. You need to question yourself and your actions in order to grow as a human being.
As for being deprived... I can't even begin to understand why someone would want to stay in a relationship where they are unsatisfied on numerous levels. Sex, you can always find elsewhere. But if you don't even have an intellectual and emotional connection, what else is left except misery??
The real question I would like to hear the answer to is from SPs who work while in relationships. If their significant other slept with someone else, is that cheating or par for the course? Does it matter if the affair was a casual encounter or paid for?
I think it all depends on what was agreed by both partners.
Being faithful means being true to your word. You can have sex with different people and still be faithful if you are in an open relationship.