As someone who hasn't been in love, Therese isn't qualified to judge whether or not Richard is in love with her. But the way he acts as their relationship falls apart makes us think that he doesn't love her.

This is Therese speaking to Richard after he basically says the same thing to her. They're around the same age, late teens to early twenties. Does anyone really know who they are at that age?

Richard believes in weird lesbian magic, it seems. Although he has heard of lesbians in society, he doesn't believe they're a normal part of society, and he clearly thinks Therese has been tricked if she's now a part of the lesbian crew.

It's difficult to tell if Richard says this because Carol is older, because she's a woman, or both. But the same-sex relationship is not acceptable in society. Richard would probably have a different reaction if Carol were a man.

Carol is right here when talking to Therese, and this recalls the earlier quote about Therese not wanting to clean up after herself. She wants to do whatever she wants without any regard for others, and Therese doesn't exactly grow out of that during the book.

Richard only feels jealous of Carol when he feels emasculated by her.

Therese constantly has to drive home the fact to Richard that she was never happy in their relationship. She never felt the same way about him that he felt about her.