You need to send him a message saying that you can no longer entertain all the texting, that you had tried to explained to him and it's obvious it hasn't got through, or he isn't prepared to do anything differently so either the texts stop, or you'll have to stop seeing him.

If he carries on after that then block.

At the end of the day, regular clients know how much we miss losing a nice part of our income. That gives them leeway to text all the time It is about manipulation but you can put a stop to it. I'd rather cut a client cold turkey and lose that income than entertain their clingy ways.

I currently have a client who is starting down this tack.I saw him once in December and he was nice enough. He sent a text afterwards to say thanks.On New Years Eve he then sent me a Happy New Year text and made reference to counting down the days when he was coming to see me in January..I guess that was the first red flag and I didn't respond.
He then booked again in January and was a little nosey in the booking but nothing too unusual just things like what I had done over Xmas and if I lived in my apartment.
Yesterday he texted me to ask if was on holiday as he could not find my advert?!? It turned out a very old advert on a site had lapsed...he then asked me if I had enough clients that I didn't need to advertise and that he thought it wasn't good for my business if I was not advertising. I pointed out to him that as well as having my own website I advertise in loads of places and not to concern himself with how I run my business.
Today he has texted asking if I give website lessons as my website is so good..I just replied with no. I think I will have to give him the speech about how it is a paid transaction and only to contact me if he is actually wishing to make a booking..but to be honest he is putting me off seeing him again anyway.