I loved ch. 2 as well. And yes I agree with you about the seme sleeping around, yes you are free to have a relationship if you are unattached but it's a jerk move to rub it in the face of your beloved. And his behaviour and explanation leads me to think that he is someone who can't go without ecchi and does not control himself very well when it comes to his "needs" or urges (lack of a better word).
All the stories are good and sweet in their own way, but I really did not like the 5th chapter with the playboy seme x cute younger brother of seme's friend. I really do not like how controlling and almost yandere possessive the seme is in that story.