Women are generally not truly loyal. I've said it before. Like the quote presented elsewhere in this thread says, when a broad is done with you, you're DONE. A girl can cry and profess her undying love and then tell you to pack your bags the very next day. Usually the dude doesn't even see it coming.
Unless there's a financial dependence or child involved, men must accept the wishy-washy nature of a woman's "loyalty".
And if you understand and accept this, it places monstrous stress on you to constantly "earn" her affections. The romantic relationship is a job, period. And this is the "in love" portion!
It really is tough for a knowing man to justify the pursuit of a lasting relationship and/or marriage.
And it hurts to say all this. I'm a romantic at heart, but I do not trust women to reciprocate my loyalty and affections.
And for the record, I've never cheated on a girlfriend. Even when I lived in another country and had opportunity present itself. My lady would NEVER have found out. Having said this, the desire to get with fresh meat is always there.
If you say otherwise, you're either a liar or a very-low-test male.