op - have a look
\link{http://www.associatedcontent.com/article/569903/is_someone_spying_on_your_pc_how_to.html\here}
hat might give you some tips as to find what you're looking for.
However it does depend on whether your dh has installed a keylogger which will only track what you do and what you type, or a remote access tool which can be used to look at any computer use i.e. he could then read the entire thread as opposed to just your contributions on it iyswim.
Tbh what I would do is go to your local car phone warehouse, and buy a pay-as-you-go mobile with internet capability, so you can surf the internet undetected.
Alternatively you should go to your local library/internet cafe and spend some time on the computer there changing all your passwords for email/facebook/mn/whatever other websites you are a member of. Then either use payg phone or internet cafes for your internet use.
Obviously it shouldn't come to that but as it clearly has, this is what you need to do for now.
And then you need to think about where you go from here and how you can get out of this situation.
Your dh is kidding himself if he thinks this won't change your relationship. Clearly he is a control freak and insecure and you need to do something about that.
Do you have children?