Hi Peacemom!
I read your post this morning, but didn't respond for two reasons. Firstly, because although I have a daughter and 3 step-daughters I haven't had the experiences that you have and you asked for people to respond who have lived what you are living. Secondly because I often read posts, think about people for a day or a night and then come up with my response.
Anyways, I was curious to see what your responses were, and sad to see that nobody really knows what to say. I'm sure someone will come through but I feel compelled to respond because I have been thinking of you often today.
I feel as though you are 90% there. Or more. You have accepted reality, and you are naturally and legitimately concerned for the consequences.
You have accepted the reality that she is going to be promiscuous regardless of how much you try and fight it. You are doing the right thing by making sure that she gets her shot every 3 months .
At this stage, now that you have accepted the reality, the next step is to prepare in case the worst happens (std etc.)
Because you have accepted this reality you now have foresight into what could happen.
Now is the time to prepare for the worst (while still hoping and working towards the best).
The question is: If the worst of the consequences happen, who is going to own them. You or her?I am not the right person to answer as I said and another reason is because as a Canadian I know nothing of medicare or medicaid.
Is it possible for her to start getting her own medicare? Can you sit down with her and let her know that if she continues this lifestyle and she develops and STD that she is going to have to be the one deal with it? Do you think your husband and you can be a team and let her know that she is now an adult and it is time to be responsible for her own medicare and if she continues to put herself at risk she has to own the consequences?
I know that you will never turn your back on her, and you would never turn your back on a grandchild.
All I am really wanting to say is that you are on the right page, you are doing the right things. You have foresight and now is the time to take steps to protect not only your daughter but yourself.
I hope this is somewhat helpful!
Thinking of you,

R