The most basic sexual abuse by primary aggressors is to obtain sex with the insincere promise of love and nurture. Any sex without full consent is sexual abuse. In any relationship where primary aggression operates, the survivor cannot be said to have the ability to consent but only the ability to submit.
Any unwanted sex is abuse. Even if the survivor enjoys the sex in someway, if the survivor is pressured into it, it is sexual abuse. Marital rape was not accepted as a concept until the 1970's. It is still not accepted as a crime, as witnessed by the fact that it has never been prosecuted in the US. Primary aggressors may pursue sexual activities with a blatant goal of power, using pain or direct physical control. In extreme cases, femicidal violence may be threatened or simulated.*
Moments of extreme feelings and extreme arousal tend to bond people, even when the experience is negative or dangerous. This is called trauma bonding. High risk and high-coercion sex certainly fits this category. It has been postulated that in some relationships of severe abuse, it is, in part, the sexual abuse that keeps the survivor attached to the primary aggressor.
Primary aggressors can threaten to have sex elsewhere if they cannot have sex when,and how they want it. An attempt is usually made to justify this by the concept that they are being refused sex. However, in this, they confuse refusal to submit to sex on the primary aggressor's terms as global refusal of sex. Primary aggressors may also sexually abuse children, especially since sex is being used for power.
Many primary aggressors have two or more relationships with women going at once. This provides a feeling of power (and perhaps a 'cushion' against the feeling of abandonment.) The blatant power behavior is either the deception itself, or, if the women know about each other, keeping them all hooked with the insincere promise that they are each the perferred women, and eventually will have him exclusively, if they please him.
Primary aggressors are almost always extremely jealous and may demand the survivor have sex to prove she isn't having sex with someone else.
*While the discussion of dominance and control in sexuality can possibly trail into the topic of mutually desired BDSM etc.., this is irrelevant to the relationships discussed here. Where primary aggression is operating in a relationship, consensual power exchange is just not possible.