Disclaimer:
I'm a woman, so if you are one of those who disregard female opinions on default, I'd be thankful if you skip this.
My background: 2 years of relationship and 2 of marriage. Age 25. Marriage is stable and sexual. Number of previous relationships: 1.
To your questions, point by point:
1. Does this mean that regardless of what I know, I will have to keep my players skills top notch?
No.
People in a mature relationship are aware of its fluidity. No reasonable person will expect you to be a top notch player in a relationship; it's even somewhat undesirable. A healthy partner is a haven to go to, when you need to relax. If your woman expects you to treat her like a player during the relationship (constant excitement, constant unpredictability, constant push-pull), she is very, very bad news. Believe me.
Being able to relax and let go, be yourself is one of the greatest features in a relationship. However, it's not to be abused. It's easy not to. Don't take her for granted and presume she'd always be there like your favorite plushie; don't let go of a reasonable standard of physical attractiveness; "date" her from time to time - say once a month; and share with her something funny you've heard every day - a joke, an anecdote, gossip. More than enough.
2. How do some of you guys keep up?
More often than not, they're just bragging. Don't believe everything you read. Especially this site is a big sausage comparing fest more often than not.
3. It seems all women have the potential to stray?
This is a hard yes. Just as it's a hard yes for men, too.
Every person has the potential to stray; however, it's just that - a potential. Most people do not even believe they could stray; and they are not lying when they claim incapability to do so - they believe it. A person in love will give a huge time window before they cheat, if they cheat for a reason other than wanting variety (and this is not that common).
However, it is your duty (yours and hers), to maintain the relationship. The best way to do this is through listening. Yes, I know, women blab on, it's just noise, yada, yada, heeey, why did she suck that guy's cock?!
It's a very sad reality where lots of people (not just women) leave or stray, because they're not listened to; and their problems are left unaddressed for a long time. A man who needed sex, but didn't get it, because any time he raised the issue he was swatted down; a woman who is overwhelmed by a job, but couldn't vent to her partner, because his Alpha majesty is too good for her problems... the list goes on. Especially those who claim they are sweet and nice guys and wonder why they are strayed on; more often than not they're so full of shit they don't even realize it. Been there, done that.
4. Is this a bad mindset to have?
Only if you get paranoid about it.
5. Makes me feel motivated to keep up with the times and shit, but it's like that little needle in the haystack that will always be there?
The times have ALWAYS be the same. People never change. If you doubt it, read Renaissance literature (Decameron, Casanova's diary). Shit happened centuries ago and it's still relevant. Aristotle said that the next generation was rotten and the world would end soon... in Ancient Greece.
6. and 7. Does anyone understand? Or am I just wasting thoughts here?
Only you will be the judge of that; depending on the quality of answers you get.