If you're getting multiple answers, assume he's seeing someone else and don't let yourself go down the rabbit hole by calling a million different psychics. There is no one psychic that's going to be good about telling you, specifically, whether or not your specific ex is seeing anyone else. Even the most reliable ones screw that up all the time.
Are you on good terms with your ex? Then ask him. If not? Then the best thing to do is move on and stop thinking about it. I know, easier said than done, but dwelling on whether or not he's with someone else isn't going to get you anywhere. Either make a move or move on.