I only can affirm everything that the OP has written.
It's like if it were 100% my own story, no joke.
And there are many others who at least at some point in time start(ed) to consider sexual activity (further refered to as SA) as a major trigger for their hairloss - in fact this topic seems to come up about every two weeks or so on any forum like this one.
And what happens everytime is that those people are mocked by the pack.
But this is no fiction folks, and only those who deny are the idiots.
And the simple reason for the mockery is: this (cause) must not be true. Because if it actually was true, this would be the worst possible news such people can imagine. And another simple reason: not every baldy may be affected.
Anyway most people would - if they had to - choose sex over hair. So, if your're one of those - fine, just do not deliberately deny.
But there apparently exist some misconceptions about this whole thing.. It is most likely not a deplation of zinc, or overproduction of testosterone or DHT, that subsequently will facilitate hairloss, nor is it the primary cause of hairloss (that is, it does not create hairloss 'out of thin air').
This problem will (apparently) only appear in those with a prediposition for hairloss; and amongst those only some seem to be affected, apparently not all. Remember that male pattern baldness is a multy-faceted disease, it's not just as simple as DHT vs hair. If the only culprit was DHT, then propecia (finasteride) would work for everyone; instead, there may be many more hormones and such involved, and many pathways to disruption to hair production.
I do not know the exact reason why in some people SA aggravates hairloss, I only can speculate.
So, regards most of you this is like to "cast pearls before swine", but who ever wants to read, I will write from my own experience.
From my own experience, SA seems to cause inflammation, possibly a stress response, possibly adrenaline is involved.
Howsoever, I'd say that it changes the hormonal setting, acutely and subsequently.
BTW, in my case not only hair is affected, but rather the skin in general, since it causes spots/pimples, preferably on the face. That is, it spurs sebum production.
The onset of this inflammation is instant and will last for some time (BTW, ever noticed the oiliness in face skin in some people engaged in sexual activity? I happened to observe this for example in some women, and usually they happen to have a 'less luxurious' mane). And further it starts a kind of cycle, this was refered to in a chinese study as 'seven day cycle' (this is only refering to men), where, if one abstains form SA, testosterone is gradualy rising up until the seventh day, and past this it basically will drop off or decline to baseline.
So, to get rid of the effect, one has to abstain beyond one week, in my case it is usually/initially (also) around the third week of abstinence when I would typically see considerable benefits, like, subsiding of inflammation (healthier hair), no pimples, and in general a relaxation/lift in mood/sense that everything is normal.
BTW, I am on finasteride and minoxidil; and I have used dutasteride and also spironolactone, and none of them were able to put breaks on that strange effect.
So, basically, if I would not abstain form SA, finasteride and friends simply would not do much for me. As they do not in many others.
Now, this would mean that since finasteride blocks the T->DHT path, a different mechanism of action is in effect here.
And let me tell you that I have observed this fenomenon in depth, as my male pattern baldness started at about the age of 17, and it was not before the age of 27 that I started finasteride and minoxidil; now I am 39 and still a NW2, although my male pattern baldness is quite aggressive, thanks to the knowledge of the connection between SA and hairloss in my case.
Otherwise I am sure I would be at a final stage of the Norwood scale.. I have discovered this connection shortly after the onset of male pattern baldness and have learnt to deal with it.
In my case this is the master principle in the fight against male pattern baldness. Basically I know that as long as I do not engage in SA, I will not go bald.
Besides that the most detrimental things to my hair are stress or any kind of feaze, and the lack of good sleep.
BTW, hi to everyone!
