Why?

Of course it matters but it's impossible to ever get the "why" most of the time.
A lot of times "the why" is a lie.

So it matters but it won't change anything and doesn't make a difference in a choice that we have to make for ourselves and our own lives.

What matters most is - "when". When is he going to fuck me?
Or "How" - How is he going to fuck me? How often is he going to fuck me?

What matters most is what I want for my life, for me.
I want sex.

I have a version of my "why" in my head. It helps me reconcile the ending of my marriage, whether or not it is the real why. Going through counseling with him, I saw that he externalized the reasons why he couldn't have sex with me, and seemed to blame everything but himself. Even blaming me, and I saw in therapy that he was using it more as a means of trying to make me fit his perception of how he wanted the relationship to continue, not change in any way to make me happy (he was happy, so of course both of us had to be happy)  But I digress.  I know I tried, I wish I had made more of a fuss sooner, but I can also look back and know I did everything I  could to try and make it work.

Chasing ones own "why" is a very worthwhile pursuit.
Mainly because you can do something about them.

Chasing a spouses "why" is of very limited value.
Mainly because you can not do a fucking thing about them.

But this question always divides along party lines pretty much.
People who are still in their ILIASM shitholes tend to hold a view that chasing a spouses' "why" has value.
People who have gotten out of their ILIASM shithole tend to hold a view that chasing a spouses' "why" does not have value.

Now given that most of the membership here are still in their ILIASM shitholes, I'd figure that the poll will reflect that fact, and I'd reckon that the end count of the poll will run at about 5 to 1. (as of right now - 9 votes cast - 78% vote that chasing the spouses "why" is valuable, whilst 22% have voted that it isn't)

Personally, back in the day of my deal, I regarded the spouses' "why" as absolutely critical knowledge to bring the matter to resolution.
Of course, where I was coming from at that point was trying to negotiate a resolution where the marriage was resolved and continued with us still together in an enhanced deal to our mutual benefit.
When I (finally) accepted that our deal was NOT going to be resolved that way (because it was completely incapable of doing so) the spousal "why" passed in to irrelevancy.
In effect, when I realised that the only resolution to our deal was to end it, chasing the spousal "why" became a pointless exercise.

Take a case like Brother heraclitus. He and his missus have embarked on a rebuild, so the "whys" of both parties are relevant.
OTOH, take a look at Brother cagedtigers set up. The spousal "why" there is redundant.

And, there are heaps more "cagedtiger" situations in here than there are "heraclitus".

The BIG danger with "why" chasing is that you think you are doing something productive when actually, you aren't.
And another danger is that "why" chasing can become your raison d'être - that this becomes your focus, your identity, your goal. That happened to me. With the focus on "why" chasing, the focus went off the real problem - that being that the marriage was a complete fuck up. The years I wasted spousal "why" chasing still annoys me to this day.

But, take Ms enna as an example. She is about the smartest chick (or bloke) I have ever come across (insert snigger here !) and it took her years to accept that the pursuit of the spousal "why" was a dead end. She used to say - "I could accept that at an intellectual level, but I would still get that feeling that there HAS TO BE 'something' I can fix in him".

I understand that an answer to the question could be very important. In my case, I finally had to decide that it didn't matter. On the wedding night when I was rejected back in 1988, I desperately wanted to know the reason so I could do something about it. For the next 22 years when the infrequent sex became more and more rare, I really wanted to know, but as the years went by, it was more for my own curiousity. Then, when I was totally cut off, I slowly came to the conclusion that the reason didn't matter, and the result was that my own needs were not being met and were unlikely to ever be met in that joke of a marriage. I realized that it was not me that was the problem, and I could and should be happy and fulfilled outside of the marriage. So I left. Now, I am realizing that I am a valuable person who has every right to have his needs met as long as I am not hurting anyone else.

Again, this is my answer, and it may not work for anyone else. But it works for me.

In a situation where 'not knowing the "why' holds you in your ILIASM deal, the refuser spouse then has a vested interest in you NOT finding out that "why", and so the smoke and mirrors method comes in to play to keep you in the dark, and still in the ILIASM shithole.

Ok I am going to debate the opposite the only reason that l led us here was the why because in life if you know the why then you can solve it .... spending your life looking for the elusive "big foot/pussy/dick" gives no closure because lets be honest in the end we will interprete anything to mean "its real" even if it out of focus image

That's not such a bad policy Sister nancyb.
Any one "why" is pretty much as good as another, so making your best guess about what a spousal "why" is, and then proceeding with getting your legal advice etc underway makes plenty of sense.
"If" by chance you got the "why" correct, it won't change anything. He'll still be as avoidant as ever.
"If" it turns out later you got the "why" wrong, it still won't change anything. He'll still be as avoidant as ever.