If you are like me, you struggle to set boundaries because the very act of setting the boundary feels nasty or mean-spirited.

It's not. Being assertive in a respectful way to the other party is not nasty.

I'm not sure what would work for you (and your H). Maybe some non-verbal body language. Maybe a simple and calmly stated "I would like if you stopped doing XYZ. Thanks!" (smile)

Also if you are like me, you may over-think things ahead of time and get your emotions stirred up, partly to give yourself the courage to stand up for yourself. Then you might come across as highly emotional, which is exactly what you are trying to avoid.

So... just think, no big deal. He may take it poorly, who cares? You'd like him to stop touching, just tell him simply and matter-of-factly. Neutral emotion. You got this!