Hello!! beta tester here so while rori gave a very nice advice (bcs yes isaac does love when you bite him) ı wanted to give my own thinking but!
spoiler alert! (about possible future events)
-the dependance, trust and affection you are building with him might openly lead you to different ending types (not like bad ending but endings with the style you chose) so you can try to pick whatever you want to see your own path ^^