My online friend is making weird accusations?

I have an on line friend who is kind of like an "msn pen pal" and i've been talking to him for almost a year. I will call him *Jack*.

Jack and I are very similar in personality and initially, we got on great. Over time our friendship has been slowly disappearing due to him suddenly accusing me of weird things such as trying to manipulate him and betraying him.

Here's what happened tonight...

Jack told me that he was reading a book about computers. I asked him if he wanted me to leave for now. He then said..."Stop it, your doing it again!".

I had no idea what I was doing but apparently he said he interpreted my asking him if he wanted me to leave as..."Yeah, I want to leave, but I want you to say you want me to leave, so I won't get blamed for this" (those exact words).

In the past, I've been offended by something that he said and stopped talking to him for a week and this has lead to him calling me an emotionally unstable manipulator, but then apologizing and saying that HE is the one with the problem.

Often at times in the middle of a seemingly normal on line conversation he will say things like..."stop it"..."just drop it"..."leave it alone"...etc and he wont elaborate on what i've said wrong.

He said that he's not sure if he trusts me, or anyone for that fact. Aside from that one time where I took offense to something he said, i've really done nothing to break the trust he had for me and it just seems that he's paranoid. I've told him that I'm not trying to get anything from him and that I'm being sincere and he goes from believing me to throwing wild accusations at me over the smallest of comments. He interprets almost anything as being suspicious.

What can I do to make our friendship better?