Try:
SELECT users.UserID, users.UserEmail, activity_user.activityID, activity_user.userid, activity_user.itemGroup, activity_user.itemType, activity_user.itemID, hadithmain.HadithID
FROM hadithmain
LEFT OUTER JOIN activity_user ON activity_user.itemID = hadithmain.HadithID AND activity_user.userid = ?
LEFT OUTER JOIN users ON users.UserID = activity_user.userid