I hope I'm not too late on this.
I've dealt with someone like this before. It's annoying, isn't it? The way he tugs at your heart strings, and then starts cutting them in half?
In my experience, the guy was still interested in me, and cared for me. But it was just how he was, his personality, that made him do the cruel things he did. For example, in your case, telling you that he was going to be with another women, and sharing her name. It's a sense of power, I think. He does care for you still, but by making you a little miserable about something like him being with someone else, is telling him that you're still attached to him.
Of course, it could be entirely different with him and you, but it sounds like that's the situation.
Either way, the easiest way to stop this from happening, is to either tell him directly that you don't want to put up with it, or stopping all contact and moving on with your chin up.