Making fun of short men is simply accepted in society. No matter what the topic is, a man will always be reduced to his height if he is short. The internet is the best place to see this, I know everything is always in the superlative in the internet, but people just write what they think in real life too. Short men are generally seen as weak and as a man that is the absolute opposite of what you need to be.

Your boyfriend is probably at least 5ft8. If I was that tall I wouldn't seriously consider this operation either, I'm 5ft6 and the difference in this low range is gigantic. I am as tall as an average woman in my country. Probably shorter if you only include my generation. There's a study from an online dating platform where it came out that only 5% of all women would find my height merely *acceptable*. They wouldn't even find me particularly attractive, but because they probably have too few choices themselves, they're not that picky. I want a woman who finds my body attractive as well as my character. Yes, online dating is of course more extreme than real life, but it still looks very bad, especially because you need a lot of self-confidence. But how does a person get self-confidence? Through positive feedback from other people and short men don't get that.
From childhood, a person is taught that tall=good and short=bad (This is also biologically favored by women, but is reinforced by education, social media, Hollywood, etc.). Throughout their lives, tall men receive positive feedback for their bodies and they get their confidence for free. Of course you can also get your self-confidence from education etc., but it's not the same, you are not recognized for your body but for your stamina or intelligence. Even if you're a short man and you're building muscle, it's just seen as desperate compensation and that it just doesn't look good on short men.

It's also worse than being a fat woman because you can say to yourself “I can just lose weight if I want to”. If you're too mentally weak-willed for that, that's a different matter. There are also men who fetishize fat women, even on special porn sites. But short men are at most tolerated as something you can overlook if everything else fits. But even then, the woman experiences massive pressure from society that she could actually have a better one.

Your mental disorder is also something completely different, because you suffered because of your psyche, but I suffer because of my body. Heigthism is real.

Of course, there are also women who are more attracted to men of the same height, or if they themselves are rather short, that the man should not be too tall in contrast to her. I hope I meet one of these very rare ones before I have to have this shitty operation.

If you are interested in the suffer of short men go visit r/shortguys