Despite it being a really short manga I was on the verge of giving it a 7/10, until the ending that feels like an open ending, and I HATE open endings.
So, unless I missed something, he doesn't start a relationship with, or confess to, either one. Based on the final chapter, and those mini-comics, he loves both of them and I'm certain that Karen has not completely given up on him. So pick one, or pick both, BUT PICK!
5/10.