Eh, they're not that bad. Momoka clearly fell for Rin early on and eventually chose to seek love elsewhere, either believing it would be impossible with Rin or just not wanting to risk losing her altogether should the confession go wrong. A rather common trope, but in this case it caused an even wider rift between them due to Rin's past bad experience with her mother. She took the chance when confronted by Rin again, but Rin's rejection at the hotel shook her again, telling her it may have been impossible after all.
And on the other hand we have Rin. Entirely lost in this, not at all knowing how to handle this relationship. Not for a moment thinking that Momoka could actually be serious about it, especially after how she described her previous relationships. Even less realizing, not before Momoka leaves her again and she starts to imagine her with others, that she herself also wants Momoka for herself.