Of course, Michael lived outside the 'bonds' of his marriage; for all intents and purposes; there were no 'bonds'; there was no covenant to observe.
As for the 'Terri' crowd, wanting the State to be involved; it was from the very beginning - by Federal Court decisions; and 'bad ones' at that.
Appreciate your 'Covenant' with your wife; but .why don't you. . .or why won't you. . .at the least, write in a Will; that you want that 'covenant' to include Living Will decisions' and that they be observed.
If it mean that much to you; then do what it takes to have your covenant legally protected; by every possibility. . .just in the case, something should just not go the way you planned it.
After the Terri fiasco my wife and I probably will get living wills. But this is also one more area in which marriage has been eroded. It is not enough that husband and wife trust each other.