sex & my bff...

So this has been going on for about 3yrs. I don't want a relationship, but he does. Whenever he begins to speak of a relationship I disconnect myself from him in every way imaginable. Recently his birthday passed and he asked me to be his date for the night, I turned it down. Later that night he called and asked me to lay with him (he usually does this, we've done this since before we ever had sex.) he tells me that he loves me & his mother has come to my mother numerous times to set something up so that her son and I can be together. I see how he's done females in the past, hence the reason why I turn down a relationship with him. We've stated no strings attached since day 1, but on his end there are strings attached. Don't get me wrong I do love him. We've been friends for over 15yrs. He's been there every step of the way. The night my 1st born was born he was there until the day we left the hospital. He was there the morning my 2nd born was there, the night I had my surgery he was there, he took my oldest to and from school just to make things easier on me. Here recently our whole connection has been more aggressive (on his end anyway). He's become extra touchy feely, there 50x more, and very possessive over the kids and I. The children adore him. The other day a girl (somehow we follow each other) she commented on a picture on my IG from 2012. She was pretty much envious of me, she said how it all makes sense. He won't pay her any mind, and that she seen the pic in his house that's how she figured out who I was. She said she sees that I am a good girl and that he need someone like me. She said that after I dropped his bday gift off he was in a trance like state after I left and he kicked all of the females out of his house. I blocked her, because I don't want any negativity.