Sounds like a mixing up of two theories: the idea that childhood abuse leads to promiscuity later in life^[1] (a purely psychological effect of unclear severity) with the differential-K theory^[2], a discredited theory^[3] from the 80s that postulated that human individuals and populations have genetic variations in the “K factor”, which leads to differences in child rearing and lifetime success outcome such as criminality:

“The more K a person is, the more likely he or she is to come from a smaller sized family, with a greater spacing of births, a lower incidence of DZ twinning, and more intensive parental care. Moreover, he or she will tend to be intelligent, altruistic, law-abiding, behaviourally restrained, maturationally delayed, lower in sex drive and longer lived.”

The theory was used to promote racism and eugenics, and its scientific foundations have since been discredited. Also the researcher who proposed it turned out to have a conflict of interest:

In particular, much of this research was supported by the Pioneer Fund, a foundation formed in 1937 to promote eugenicist and racist goals.^[4]

In any case, r/K selection was supposed to be governed by genetics, something a human already has and can’t be changed during a lifetime. To claim that something that happens during childhood changes the “K factor” is neo-Lamarckism, unless it’s claimed to be an epigenetic effect like transgenerational trauma:^[5]

The mechanism for transmission of trauma may be via epigenetic modifications introduced by stress, passed down via environmental or cultural conditions.

But such epigenetic human effects are also currently disputed.