Bella like everyone else in the game is only human and that what makes her character interesting ! In fact, I think every LI had at least one contradictory or hypocritical feeling but we love them anyway.
Bella even recognise it in the infamous Cathy panty scene... After seeing it again, I think she'll be ready to let the MC go if he gets serious with Jill. But it's too early to tell...
Bella if her path is active is mostly torn between her heart and her lust... Isn't that the core principle of Being a DIK
She wants Jill to be happy with her relationship but she also wants the MC... She wants to stay faithful but she also wants to have sex with the MC... She's very complex... And you're right maybe deep down she wants to be caught.
Bella is hot and a complex charcter and that why we love her