So, I rejected my best friend. Now he refuses to date anyone else. Thoughts?

Even though I don't want to date him, and he accepts that, he won't date anyone else because that would be a "betrayal". His logic seems to be that if he can't date me, he can't date anyone.

He's been at this for 4 years. He furiously argues that no girls like him whenever I point out to him a girl seems to take an interest in him. I worry because he really makes himself miserable doing this. How do I convince him that he's wrong?

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1 y
Just some extra details I mentioned in replying to comments:

I've dated quite a bit and am in a relationship now. He doesn't show any hostility towards my relationship and actually gets on with my boyfriend perfectly well.

In those 4 years, he's helped me when I wasn't happy or was abused by other guys and he's kept a healthy distance when I'm happy with other guys.

It's more like he simply refuses to date out of principle or as a self inflicted punishment for even asking me out.
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1 y
When I explain that another girl likes him, he gets angry, less at me and more at himself. I think it's a severe self-loathing reaction to rejection.
So, I rejected my best friend. Now he refuses to date anyone else. Thoughts?
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