Please, don't worry about it. I know it must have been upsetting, but there's nothing wrong. There could be a number of different reasons why he did that. But you have to keep in mind that finding a language partner is similar to looking for a friend. Some people are just not a good match. I can't speak freely with just anyone, so I sometimes feel awkward or I hardly understand the other person. But other times I am so surprised to find myself talking freely... that means the person and I have personalities that fit well. Try to talk to someone else and please forget about that guy.

Well..............SHit Happens......

I sometimes can have same situation and in the case I can be depressed some time and I also thought what is wrong with me and I was very sad when my friends left from my contacts. Now I try to talk and look for my people with whom I can talk freely and sometimes I meet such people. I try to remember if I showed my kindness and my partner went out from my contacts or our conversation it can be not my problem.

Maybe it's not not your problem, but his one.