Why does my partner accuse me of the lies he tells?
Because he has a serious problem facing his own truth and wants
to put it off on someone else. That is what immature, inconsiderate
people do, its mental abuse and you need to point it out to him or
get out. He will never change. The best guess that one could have
regarding "why" is that no one knows. That is, you can't really
ever know what someone else is thinking. One thing for sure is that
this action does unnerve the victim because it is not true and
often comes out of the blue. Avoid trying to explain in any shape
or form why you haven't done what he says since that is not what it
will take to safely answer the accusations. Take what he says as a
strong hint as to HIS actions, and reconsider your relationship. He
has to do the work that you can't to solve this behavior.