Strong men are made, not born.
An alpha male is a strong masculine man. Strong either physically, emotionally, mentally, intellectually and/or in any other way. Independence, achievement and adventurous fun are part of what make men masculine. Masculine traits in men give women tingles.
A beta male is a male who has more feminine traits. Traits such as caring, nurturing, consistency and steadiness are some of the traits that are beta in nature. They're the more feminine elements of being male, although they aren't quite the same as the feminine of females. It's sort of like feminine within masculine.
Beta traits are important to women because to build a family and raise children you need the steadiness, nurturing and soft side to emerge. Dangerous fun might be titillating and arousing, but it's destructive to raising a family.
This creates a big problem. You need the steady commitment and nurturing of the beta in order to have a stable, long lasting marriage. However, women naturally find such men boring and that means diminishing desire for sex. This can lead to frustration and resentment from the husband and boredom and unhappiness from the wife. Both can lead to adultery, a miserable marriage and/or divorce.
OTOH, choosing an alpha male isn't simple either. Alpha men have a lot of options and aren't necessarily inclined to settle down with any one woman. They're able to have many flings along with all their other adventures.
The default setting
Anyone who is a parent to boys and girls will probably know that they are very different even from a very young age. Boys are much more rambunctious, wild and destructive as toddlers. When they grow older, they may not like girls because girl germs. They keep developing their masculine self if they're allowed to and aren't shamed or discouraged by their parents and teachers.
All this changes the minute they hit puberty. All the macho independence flies out the window and the boys become the biggest simps, melting into soft butter in the presence of an eligible female! This is because it's hardwired into men to desire women with this insane level of desire, to be soft and kind to women, to be giving and caring to women and to bend over backwards to fulfill her every wish and desire. These traits make him a beta male and are not good for the female sex drive. This is the default setting.
Men can learn to be more masculine, but this does not come naturally. There's no such thing as a natural alpha. You may think he's a natural because you met him once he's been in this world for 2-3 decades or more, once he's been through many rejections in life, once he's had time to hone his masculine side. All this comes with hard work, none of it is natural. Naturally, he's programmed to be smitten with immense sexual desire for the female and to do whatever she wants in the hopes of the actualization of this desire.
Who ought to change?
This question really deserves it's own post, but the short answer is - both of you need to change. He needs to go against his nature of bending over backwards to pleas you to start standing up to you and to stop being a pushover to your every whim. You need to go against your nature of making demands on him to fulfill said whims, of criticizing him when he doesn't get it right or of nagging him when he doesn't move fast enough to do what you think he needs to do.
He needs to go against his nature of repressing all emotions and to be a little vulnerable and establish emotional intimacy with you. You in turn need to find sexual appeal in the things he does for you by viewing them as acts of strength. You need to be appreciative of his steady support, caring and nurturing and never take it for granted.
Marriage requires a fine balance of many opposing traits. Harmony is when such balance is achieved. Both men and women need to recalibrate towards the middle in order to achieve such balance. This is something our great grandparents knew, but this wisdom has been somewhat forgotten in an age where we all expect the other person to make all the accommodations.
So if you're ever thinking to yourself - my husband is so beta (or any other trait that you find undesirable), can I get him to change? You need to do two things right away. 1. Look in the mirror and see what you can change. 2. Learn to view his trait from a different angle, an angle that might make the same trait look appealing and attractive.
If you need to look at the cup being half full instead of half empty, perhaps your cup is twice as large as what it ought to be....