DISCLAIMER: I am neither a doctor nor a lawyer nor a clinical researcher, I have no formal training in science beyond simple undergraduate neurobiology. This is conjecture and opinion only. Do not use this information to diagnose or treat any disease.
As part of the fact that I'm dealing with a spouse who is not that far removed from initial inpatient detox, I have done quite a bit of reading about the alcoholic brain and how alcohol itself is addictive.
I have also been reading several online blogs and private Facebook support groups for relatives of alcoholics, and as is typical of Al-Anon almost all of the contributors have been female. I've read litany after litany of quiet, desperate woe in which the women feel rejected, worthless and ugly because when their husbands were drinking, they weren't interested in the beer breath and the drunken fumbling and had no libido themselves. But after inpatient or outpatient detox, they were affectionate and sexual, for a while. Then they reverted back to indifference, which left a huge psychic scar on the self esteem of a lot of these women.
In comes my theory.
Especially in the alcoholic brain, but in every brain anyway - alcohol triggers endorphins, which bind to opiate receptors. In plain and simple language, you have a heroin/morphine high, which is why it becomes dangerously addictive in some people. Not as much, but still, on that spectrum. As a West Coast alum who's seen people shoot up in alleyways, and have had acquaintances of acquaintances use, heroin takes away your interest in sex. Because it slams into your opiate receptors, it takes away any other normal human desires that otherwise trigger those receptors. Heroin addicts lose interest in eating, and they also lose interest in sex, or anything else otherwise pleasurable.
So what I postulate is happening here is:
Alcoholic husband goes through life in a constant endorphin/opiate high.
Something happens (jail, rock bottom, etc.) that makes alcoholic husband go to inpatient or outpatient detox.
Meds are provided to prevent delirium tremens and such, but the opiate receptors are no longer being lit up by booze.
Hence, when said alcoholic husband gets out he's clean, he's sober, she's eager to see him again after his absence, he's not got beer breath and his brain is seeking opiates of any kind. Sex works.
But within a week, the brain has settled down to its new normal, and other things come into play, like depression which is a known libido killer, as are ongoing anti-craving meds. Naltrexone has varying effects on different men, but in many it increases prolactin, decreases testosterone and kills libido.
I feel for the women who've seen a sudden uptick in passionate sex, followed by a dead bedroom, especially since a lot of women see that as a reflection of their innate attractiveness and femininity. Pile on that the feelings of guilt of not wanting to complicate the life of someone in recovery and the decided need to remove stressors from the person in recovery's life, and you have a very bitter and lonely period for them.