Women (and men) get an ego boost from having an attractive partner to their sex. Men get it through physical attraction of their women. Women get it through 'alpha'-ness (status, wealth, confidence/dark-triad). When the 'alpha' is wanting or waning, her ego and confidence falls. So naturally, she seeks short-term boosts such as stepping above him, fishing for compliments, and other beta-whipping behavior. It doesn't help most of this is culturally regarded as something women 'should' want.

Even a monogamous marriage makes women want their man less because he needs to be sexually held in high regard by other women. Divorce rates are not just because of sexual 'hypergamy' but because marriage goes against a primal sexual turn-on for women - the sexual validation of her partner amongst other women. Sudden changes in sexual behavior after marriage make sense in this way because she suddenly doesn't see her man as sexual object when he's a safe trinket.

In short, beta-ization is just women trying to find what she can do to fulfill a sudden ego and sexual excitement loss.