I agree with Faith Seeker with the following addendum:
I'm not sure how much general knowledge you are coming in with, so please realize that it is your mind where you exercise complete authority, but there are real energies being manipulated when we direct our thoughts in certain ways.
Also, it may be irrelevant whether he is psychically attacking you. It is possible for this energy to be sent to you unintentionally or even without his awareness.
Either way, his energy is present in your energy field (or aura) and you don't want any uninvited foriegn energy influencing you.
A simple technique you can use to exercise your intention to remove this energy would be to visualize a rope or cord (A grounding cord) running from you (if you are aware of chakras you could plug it into your root chakra, if not you can attach it anywhere on your body) and going all the way down to the center of the Earth. Picture it secured there. Then visualize and intend that any energy not belonging to you is draining down the cord and being cleansed by the fiery heat at the center of the Earth.
This does not require strain. Simply understand that just as electricity flows down a copper wire to ground, energies not your own naturally flow down your grounding cord to Earth and are purified.
When you feel all the unwanted energy is gone, you can picture yourself rolling up the cord and toss it away, seeing it disintegrate.
You then might want to consider visualizing a ward - some object you feel secure with. It might be an animal type you like, or a mirror , or a little shield - you get to choose. But see it floating around at the edge of your aura, and intend that it is a guard, and will stop any other energies from invading your space, unless you invite them.
You should also call any energy you may have left with him back (by intending it return to you). You don't have to answer a phone call, but if you call someone they can talk back to you. :)
Sorry if this is more than you wanted, but I thought you might like a specific technique. And of course it isn't the only way to go, just one way you can go.
Be Happy and Blessed.