/////48 year old woman zero sex drive any ideas?////
That is not an unusual state of affairs and I might go further and say it is the normal.
If it is causing little or no problems in your marriage, then don't beat yourself up about it.
Knowing your past history as I do, then it is unlikely to have a physical cause as you have regular blood analysis.
The cause is probably psychological or down to routine sexual boredom.
An affair may well solve your problem, but Knowing you as I do, that is not an option.
Who needs sex most..?.you or your husband?
If it is not bothering either of you, then live with it.
A difficult problem which EVERY marriage goes through.
I am not an expert on the psychology of sex, but you will not be short of helpful answers.