I think that what you are saying when you say "however hard that may for either of us" what you are really saying is "it is difficult for me". I think you should refrain from being presumptive about what his emotions are, even when you are sure what they are. Let him state his own emotions when he wants to.
The boundary has been set, he knows what it is, now he has to make the choices. He may decide that his love for you is enough, he may decide that it isn't worth as much as drinking.
I don't see it as giving away your power by being honest. But I do think that he already knows you are emotional about him.
I agree that you don't want to say anything which gives him the idea that he can get you back and continue drinking. If you write things that send the message that you are feeling very weak and emotional, he will run with it.