In most cases, exceptions being a negligable minority, there is no need to go back to the person unless a good friendship is all you're planning. Even then some people are simply unable to remain friends with those they have once been romantically entangled with. But pulling back and reapproaching from another angle is a tactic that can and will work, but only after a somewhat extended period of time. If you try to do so too quickly they'll see through you and push you away even more. If you do it too late you're no longer a part of their lives and they won't care. If you've practiced this tactic before and have become a master of your timing then it's entirely possible you can pull it off. If not don't try it. Personally I'd advise simply moving on. He's not into it and trying different courses to change his mind is very time and effort consuming and will provide you with minimal results.

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Heit ist mein taug.