You have always been a hedonist, and ~he is there to indulge with you, with an animal hunger that matches your own.
The sexual compatibility between Machado and her girlfriend here, to me, is parallel to the sexual compatibility between Yunior and Miss Lora. Machado is not too keen of her girlfriend, yet she is drawn to her by sex. The same can be said for Yunior—he wants to stop seeing Miss Lora, and is reluctant to see her even, but time and time again, he finds himself back in her apartment because of their sexual compatibility (among other reasons). This makes me realize how significant sex is when it comes to attachment to an individual. There doesn't have to be such an emotional bond or tie to the person for one to engage in sexual intercourse, but simply a common attitude and yearning for sexual desire. I think that this is what blinds Machado in some way and makes it difficult for her to leave the abusive relationship. Same with Yunior in Miss Lora.