How could he lead me on?

He took advantage of the attention you provided. Either to his ego or things he desired at that time. Don’t beat yourself up though. Once you know exactly what he wanted from you, you let him know how you feel about that. Never let someone treat you like you don’t have control of the situation and that you’re not worth being seen for ALL of you, not the things they only want to see. I’m sorry you had to go through that, those situations are always the worst. Just know, you’re amazing and you deserve someone who’s going to want all of you, puts effort in you and doesn’t lead you on at all. I wish you the best.