So I have a theory, despite how she's acting. I think despite Stella being upset and forceful. Ahe has feelings for Trevor. I think Jessica purposefully told Stella because she knew. 

I think it made Stella certain Trevor could satisfy her and she decided to do what she felt was necessary. I think on one hand she grew to use this personally both from hurt he stayed away to using it to hopefully get him to listen. She's not forcing herself so I figure she's at least hoping he goes along with it. I feel for Trevor and how he feels, in truth I think if this works out maybe things will feel better for th3 two.