This is something that happens more in the higher SMV communities, i.e. 7+ women and beta males.
If you've been with the same faithful woman for some time you are clearly an alpha male to her (you're not actually an alpha though, because alphas don't settle down, they pump-and-dump) as her SMV is so low she thinks she's won the mating lottery with you.
Plus, let's be real here, I know we're not dealing with 10s here (or even 6-9s).
Just know, most women absolutely cannot say no to alpha cock. If she's young and a horny Chad presents himself she'll take a bite. You don't stand a chance.