Morning, Dog. I am proud that you expressed your feelings honestly, and without anger. You did good!
I also honed on a the part about her saying you'd act like a little boy when there was a dry spell in your dating days.... and a huge lightbulb went off for me. Dog, if (lack of) sex was present before marriage..... well, naturally it would continue and worsen! you missed a huge red flag, signaling what your future would be like with this woman!
I did the same thing-- there were red flags about sex when I was not yet married to my wasband... I wanted sex more than he did, he made a comment about not wanting to do something if it was "expected"-- it was a long time ago. But it escalated to passive aggressive withholding of sex.
Looking back I can see the red flags clearly, but hell, at the time I was 21 and naive. I did the best I could. But, I can sure do better NOW!
Anyway, this not wanting sex may well be part of the "package" deal you signed up for in Mrs Hairdog. This would explain why she has dug her heels in so deeply; you accepted it at the beginning, she thought it was "settled".
I think you better hold your ground pretty firmly now if you are to have any chance of improving the situation you're in.
As for her remark that most marriages are like being siblings? I know that's the case sometimes, but not the good ones, not the ones that last. It's very sad when that's the case, very sad indeed. IF that's truly what she wants, you have another discussion to have-- one that maybe should have occurred much sooner (ie before you got serious) but better late than never. You two need to sit down and determine what it is you are looking for out of the marriage, relationship! I'm beginning to think the lists are quite different.