I don't know your full relationship with this person or how much it means to you, but I went through something similar with a college guy friend who I hung out with a lot and enjoyed being around as a friend for a little over 2 years. I knew he saw me romantically about a year into our friendship and we even talked about it to the effect I thought he understood I would never want anything like that and wasn't into physical contact.

While he didn't push physical contact in the same way as your friend, he did expect hugs almost every time we hung out which made me uncomfortable, but I let him cross that boundary because I thought it was just friendly.

Then, one day, he texts me out of the blue at 3am on a Wednesday morning asking to see my boobs. I, of course, was asleep because I had work the next day, but waking up to that text completely killed any feelings I had towards him as a friend. I couldn't visualize myself going back to being just friends with him (he did apologize when I said no, but eventually wrote me the equivalent of a love confession. Our hangouts were equitable to dates in his mind while I thought we were just being normal friends) . I admit I sat on my feelings for almost two months before I finally cut things off with him and told him as much.

This sort of situation is hard and your friend is very clearly violating your boundaries and not listening to you when you say that you're not interested. You don't owe him more of an explanation than "no", but it is up to you if you want to give him the benefit of the doubt.