>>96646034He can’t bring himself to end the relationship and thus giving Heidi freedom of choice, she’s a property and so Cartman can’t stand the idea of his belongings moving on to other people. Cartman thinks of Heidi as a tool that exists with the only purpose of being at his disposition to offer him constant attention and validation, nothing more, nothing less.
Simultaneously, Cartman can’t stand Heidi, because she doesn’t fit the description of Cartman’s ideal image of her. Naturally, Heidi isn’t the tool Cartman expects her to be, she is an human being with her own individual needs. Whereas Cartman looks for a relationship where he is the center of attention, never giving anything in return, and a partner willing to follow him blindly against all the odds, without him having to worry about losing their support; Heidi looks for a functional, healthy romantic relationship, were all the parties involved contribute their part. Cartman is unwilling to fulfill this role, because doing so would position him as an equal of Heidi’s, which means, to him, degrade him from his high-entity status.