I'm not sure what to write with regard to this, x123. I'm in my mid 60's & I know that men's libidos do decrease with age. Mine has all but disappeared. I've never heard of the brain becoming dependent on sex for normal functioning.

I don't know how long you've struggled with chronic depression. But it is certainly also true, I believe, that depression does over time wear the brain down in a variety of ways. I sometimes wonder if I might be suffering with early onset dementia or Alzheimer's Disease. But really I think it's mostly just due to years & years of depression & anxiety. This may be what's going on with you. It may be just a "perfect storm" of age-related decreased libido & the effects of chronic depression.

You didn't mention anything about your employment status. But, if you're unhappy with your employment situation, or if you're not able to work & having financial difficulties, these may also be contributing factors as well.

The other thing that occurs to me is the possibility that you might have low testosterone. I'm a YouTuber & I subscribe to a YouTube channel called: "BigNoKnow" Noah Thomas, whose channel this is suffered a major breakdown as a result of having low testosterone. He became severely depressed & suicidal & suffered from depersonalization. Noah uploads videos on the topics of the effects of low testosterone as well as depression, anxiety, depersonalization, & alcohol dependency with which he has also struggled. If you haven't had your testosterone level checked it may be worth the effort to have it done. (You might also take a look at Noah's YouTube channel.)