How to get over it?

I dated this guy who was my first love & everything who turned out to be a douche... And basically he called me fat, well his exact words being "I wish you were skinnier"

For some reason this really deeply hurt me as I actually already lost a lot of weight at that point.. Anyways how do I get over this and just learn to toughen up and stop being so impacted by what he said? I just felt my self confidence drop after that sadly.
How to get over it?
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