How do I make him treat me differently?

I've ended up getting with my boss. At the start when he wanted to get with me he was always messaging me and complimenting me. He'd always say how perfect I was for him and that I was hot and I could be his mistress if I wanted. I was really not keen and then we cuddled for a while and I decided I wanted it, so I agreed and he was still the same just so lovely and he would sneakily kiss me at work when we're alone and send me messages even he was in the same room as me making me feel special and now a couple of months down the line he just isn't interested. I go up and do whatever and then I leave pretty much straight away. Before he was always messaging me about times we could meet and now it's only me that does that, he doesn't bother. Am I giving it to him too easy? and how do I make him want to be like he was at the start without pushing him away? I want him to chase me more and make me feel like I did when I got with him.