Why would he assume this?
Me and my ex have been talking as friends and everything was fine. Then he found out from a mutual friend that I want to get back together with him. He then just assumed that I'm talking to him to try to get back together, and started treating me like a desperate obsessive ex.
My question is, why would he just assume that? Just because you want to get back together with someone, doesn't mean you're TRYING to.
Have you ever heard those stories about someone who is deeply in love with their friend? Every night they cry because the friend doesn't feel the same way. But they always put a smile on and hide it. They suppress their feelings, they don't express them because they know the other person doesn't feel the same. So they just keep it inside. That person is not trying to get with the friend at all! They're just keeping their feelings inside because they accepted that they cannot be together.
Trying to get with the friend would be if they are flirting, trying to get close, asking them on dates, etc. (because they are acting on their feelings rather than suppressing them. They are trying to make things go forward instead of accepting how they are now).
So just because you want to be with someone doesn't mean you're trying to. I wanted to be with him, but I hid my feelings and I kept it to myself. I think it was quite considerate of me to respect how he feels and not push anything on him. So how can he interpret it as me trying to get with him; how can he treat me like a pushy desperate ex when I was actually being the opposite (a respectful considerate one)!