I think he wanted Kaede to be more possessive of the things Kaede want. By making Kaede come after him.
That was also my thoughts but i find it a bit stupid. I hate someone who is manipulative （￣へ￣）
I think it's that he was a little bit bored of how the relationship was progressing, so he had his friend help him push his lover away, but he didn't tell her that it was to force his lover to either give up entirely (he really didn't want that) or to finally pursue him.
As much as I like this manga, he's a manipulative jerk, and it taints the story, and I feel bad for the uke.
Just look at how he first gets together with the uke - he tells him that his flowers suck but that he's the only one who can help him, then he makes it seem like the uke's father is the one who wants him to teach his son, then he forces himself onto the uke and pretends that this is the only way to make his flowers better (knowing that the kid is heartbroken and vulnerable) - the seme even said that he fell in love at first sight and decided that he was going to pretty much do whatever he had to in order to make the uke his. Then the manipulation at the end... Poor Kaede, to be caught by a seme like that.
And I was like: "SOMEONE PLEASE SAVE KAEDE FROM THIS JERK. OH MY POOR LITTLE UKE. "
And now, I'm just imagining an alternative ending which is Kaede meet someone who's better than him hahahah ╮(￣▽￣)╭
So this might be a dumb question but, did Hikawa want to break up with Kaede? I just dont understand because the speech the lady gives Kaede here, http://www.mangago.me/read-manga/ore_no_mune_de_sake/tr/26267/page/182/ and then the phone call http://www.mangago.me/read-manga/ore_no_mune_de_sake/tr/26267/page/197/. Was that what she was talking about the manipulating the break up? Did Hikawa ask her to give Kaede the warning?