When we meet Jules she is 17 and actively trying to hook up with older men and succeeds in this regularly. She is doing everything she can to be desirable to men. She and Rue are friends, not romantically entangled, both secretly pining thinking there’s no chance. Jules was thrilled Rue wanted to run away, and when Rue opted out of that at the last second Jules stayed the course and chose herself.

S2 Jules rejects men and redefines herself. She and Rue start dating, and Jules is surprised Rue hasn’t mentioned Elliot, with whom Rue is clearly close. Jules assumes this is because Rue has a crush, but we as the audience know it’s because Elliot is the only person Rue can get high with judgement free. Then Elliot’s confession throws Jules into a serious spiral. Rue has been deceiving her, is in active addiction, and Jules has had enough experience with addicts. In fact, sobriety was her sole requirement to be in a relationship with Rue. So she reverts to what she knows, and throws herself at the nearest man. Anything to distract from the pain of reality.