My son is also very physically affectionate, in addition to still breastfeeding and I am constantly touched out. I've recently started telling him my body needs some space for a while and suggesting other things he could give a big hug/ squeeze to like one of his stuffed animals. I also got him a weighted blanket and will get some weighted stuffed animals as well, for more sensory input.
@Melissa thanks!! That's a great idea
You are not alone! I am my mom’s only child, plus being a single mom to a child whose love language is physical touch. I just set boundaries, I give her what she needs for as much as I can take and I tell her that is enough now. I believe it also teaches her self control because us as humans nothing is ever enough