Most Helpful Guy
I think you're getting a distorted view from what you're hearing. There are many guys who will be loyal. There are also many women who will not be. I don't really think that the percentage of men that cheat is much, if any, higher than the percentage of women that do.
I also think that most people won't cheat if they are satisfied with their relationship. The problem is that keeping both people happy in a relationship isn't always easy. In fact sometimes it's hard. And a lot of people, instead of doing the work necessary to keep their existing relationship going well will instead take what they think is the easy way out by getting together with someone else that gives them what they want (at least for a while) without making them do the work required for a long term relationship. Also, couples with significantly different sex drives have the risk of the person with the higher sex drive getting so frustrated because their partner often isn't willing when they are that they eventually succumb to the powerful force of their sex drive and seek satisfaction elsewhere.
However, if a couple is sexually compatible (not meaning exactly alike but close enough that they can reach a mutually acceptable compromise) and are willing to work through the challenges of disagreements and work together to find solutions they both are happy with and treat each other well, then I personally think the risk of either of them cheating is low. I think it's the relationships where the couple isn't really compatible or at least one of them is unable or unwilling to work together and compromise on the things they disagree on are the ones where most of the cheating you hear about occurs.
Most Helpful Girl
women actually cheat just as often as men. i think men get caught more frequently because women are sneakier. i have no idea why people are so terrible at being loyal - it's sad!