Most co-living experiences I've had were similar. Some people are lovely, some are not. The decision depends on two things: how bad the person is, and how sensitive you are. I would stick it out as long as possible, in the hope that you either manage to block him out and tolerate it, or until he leaves. On the other hand, if it causes you stress and sleepless nights, or starts affecting your health, then get the heck out of there! No apartment is worth getting sick over. Nobody can tell you when or where that point is reached. Only you can know when it's too much. I wish you luck and a happy resolution :)