Alright, so while I've banged around with a lot of athletes, I'm still lacking in certain sports, NBA and NFL respectively (Nick Schommer, you still have a chance to be part of history). However, from hearing stories from a friend who actually knows way more about sports than I do, I think basketball is probably the best breeding ground for cheating dbags.
Most would think baseball because of the schedules. Dudes who play ball are away from home sometimes two, three weeks at a time for series. However, because in theory every day is game day, I don't think baseballers' schedules increase the cheating. It makes it possible, yes, but I don't think it makes it more frequent.
Basketball is this weird sport of a lot of money, a lot of bling, a lot of over indulgence and promotion. More so, in my opinion, than any other sport. To me, it's a huge sport of celebrity show off. And because of that, I think the attitudes attributed with basketball players make for a ripe old "fuck the chick who's not your wife or girlfriend" fest.
A friend of mine who works for a sports magazine was telling me a story about how, I think it was someone on the Lakers...or no...yeah the Lakers, I'm almost positive, was hittin her up and hittin her up and finally asked her to come out to Cali for a game. Then she realized he had her up in a different hotel. And she knew that he was probably getting a bunch of bitches together for this, keeping them separate, and having a grand ol' time. So she politely declined.
So yeah, to me, basketball just seems to be partial because of the people involved. There are a lot of money hungry bitches who go for basketball players because of all sports, I think basketball players exude the "life" in the public sphere the most. Baseball players and football players might have more money in certain cases, but for some reason, basketball guys are a little more in the celebrity limelight, I think because basketball is so often connected with the celebrity circuit. And so you have some hard core jersey chasers who want to be famous and want the money and want that lifestyle, they want to be buds with Jay-Z and Spike Lee and Jack Nicholson, so they also won't mind looking the other way when their dude slips the dick to a few unknown vajayjays every now and then.
As for other sports....to me, I've probably seen the worst examples of cheating with soccer. The international thing just makes it pretty easy, I think. Plus, the dudes are hotter than the average sport, so they get some hotter options as well.
As for the most faithful....ehhh, every sport has its cheaters, but from what I've seen, I'd go hockey. I've seen some of these guys have "open" relationships with their gf's from home, but they are also like 21, and it's only girlfriends. The only time I've seen a remote hint of marital sitch is when an older hockey dude was wasted and asked my best friend what kind of underwear she had on at bar, to which she replied "you were just talking about your kids". He finished his beer and moved on. Even my old hockey dude is now in a happily Canadian relationship, and I don't think he'd cheat. I feel like hockey doesn't have the flare for dramatics like other sports, and therefore a lot of the jersey chasing doesn't hit close to home. Plus, have you seen majority of the chicks who go to hockey games specifically on the hope of meeting a player? They are ALWAYS overweight, they ALWAYS have gross curly hair that they put too much gel in so it's rock hard, they always have glasses, bad skin and no concept of the invention of foundation, and you always question whether they are 37 year old nerds or 14 year old "awkward stage" 9th graders. And they are always wearing a jersey, thinking their love of the sport and game and team with somehow give them a leg up. False. The options there just, in my opinion, aren't as good.