Why do guys lead girls on?

Ok so a guy and I had a bit of a thing anyway after several months he went hot and cold so I approached him and he said he liked me but he didn’t want to lead me on, but now he can barely acknowledge or say hi to me. I mean why does it literally have to be all or nothing? He acts like a stranger now and after everything I am pissed.

Surely it’s the decent thing to do is acknowledge someone you had a history with and the thing is the way he had been I wouldn’t want anything to do with him romantically after how he has been.

Why do guys lead girls on?
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