How do you get through to someone??

Okay so the issue is that I have this friend who won’t listen to me when I tell him that I am taken and just want to be friends. How do you get through to them that you will never be anything more than friends? He is continuously talking to ms like we’re together and I am getting very irritated. Tonight he asked me if he could watch me get ready for bed and then asked what I was wearing. Is that not something your significant other would say to you or ask you? He also keeps calling me baby and saying that he loves me and all this romantic stuff. I have told him a few times before that we are just friends that I am taken and will never be with him but he doesn’t stop. He continuously say sexual stuff to me too and it just drives me crazy. I am getting close to blocking him but I really don’t want to do that. Does anyone have any advice or suggestions for me? If so I am all ears. I just really want to know how to go about getting through to him and getting him to stop the crap. Please help.