The MC was hesitating over calling Josy when the phone rang. At the end of the date we see the MC saying 'Maybe I should -' when Josy interrupts him and invites him to bed. Every time we see the MC having second thoughts.
Show me dialogue from the game where the MC is leading Josy on. You just won't admit the truth, shown in game.
There's plenty of dialogue if you look for it, the question is one of intent. You assert - without any proof, I might add - that Josy is deliberately misleading the MC purely to keep him around her. If we assume the MC is likewise motivated purely by a selfish desire to use Josy for his own benefit, there are several occasions where he clearly signals his "interest" in Josy.
For example, immediately after the first date ends and he says it might be better if he didn't see her again, he gives her his sweatshirt. Note that this is before her "not farewell" line, so the MC is the one who begins the trend of implicitly showing interest in despite saying they should break ties.
Then there's the call on the first night of college. Josy says it was a mistake to call, and the MC immediately asks to come visit her. You assert that Josy interrupts the MC when he has second thoughts. Here the MC does that same thing to her.
There's also the the MC's response when Tina tells him Josy quit her job. Josy isn't here to interrupt and there are no second thoughts. He's still determined to keep her, all on his own initiative.
Finally, we have the dialog in their second date just before she offers to let the MC spend the night. Josy explains that she is feeling guilty. The MC, without any interrupted second thoughts, suggests that she she wants more to happen with the MC. Would Josy have made her offer if the MC didn't lead her into it?
To be clear, I don't think the MC was manipulating Josy any more than Josy was manipulating him. I think both of them wanted contradictory things: to respect Josy's existing relationship, and to act on their mutual feelings for each other. Unsurprisingly, that results in a lot of mixed signals and intimate heart-to-heart moments between the two.
If you insist on viewing Josy as the villain in this, I can't stop you. But I'm not aware of any evidence from the game that explicitly supports your view and refutes mine. So I suspect we're just going to have to agree to disagree.