Aren't we all making massive assumptions about God? At least the ones in my note are based on Scripture.
I haven't seen that "presumed" in your notes before. Lets try it out: "... the PRESUMED original sacramental bond PRESUMABLY still exists therefore the second relationship is adulterous." I can't decide which placement you'd prefer, so you can choose. Or you could add it to the conclusion "we presume the second marriage is adulterous." That seems like a better starting point to me.

It seems very odd to me that you say the Church "presumes" and later in your note you condemn "presumption." I wouldnt even have gone that far in talking about your assignments of mortal sin, though now that you suggest it...