If you're in a relationship with her, then you should have built rapport, enough to keep her from fucking another dude trying to game her. If you haven't, then your game isn't tight enough. And your game should better than any other PUA trying to approach her.

Why don't all wives randomly fuck any guy that comes along more Alpha than their husbands? Social dynamics isn't black and white. Sure women are hypergamous, but that doesn't mean they will immediately forgo a prior emotional bond to satisfy their immediate attraction for another man. This is where stuff like deep rapport, building an emotional bond, and creating a solid foundation comes into play.
It's not black and white. It's not "He's using PUA techniques...so he must get laid." There's a thousand variables that come into play. Different people naturally clique better with each other because of how they were sexually imprinted / psychologically anchored to perceive attractive qualities. And then there's social proof, your own frame, how you handle a girl's shit tests, and your interests.

On top of that, it's not just an "ability." It's a skill, and some people are better at it than others. Do you think if you went up to George Clooney's girlfriend and used a PUA technique that she'd consider you as Alpha as him?

And you're misconstruing female hypergamy. Some girls are very attracted to musicians - perhaps because they look up to men who can create audible art. So guys who can play instruments can greatly increase their chances by using said "PUA tactics." But if another guy, say a rich business man, approached the same girl, she might not look up to him in the same way. Don't think of it linearly, it's far more complex than that.

You have a very myopic perception of game, your misconceptions/ questions are symptomatic of your lack of knowledge and understanding.

I think his girls is always stolen by somebody else that is why he always asking question for him to more careful if ever he has another girl.