Mostly, because it was very strong for the first 2 months after Dday, and was helping me to feel close to her and cope with things. Now, it's like a huge stab in the gut that I'm having these issues and her desire is waning.
You will still be riding the rollercoaster, as you are still too near the DD date. This swinging of emotions and chaotic thoughts will still be with you, as you have experienced trauma.
Give it time and some counselling, and you will be able to get it under control. Focus on IC first, and think about MC later, as the M is technically dead, and will not go anywhere, whilst you are still 'alive' and struggling.
She says that sex is no big deal to her.
Does she mean with you, or it was no big deal during her AP?
She tells me that I'm overthinking things with the A, sex, etc., and that it would help us if I just focused on the future.
This to me, indicates that she lacks empathy for you. She is effectively telling you to 'get over it'. She is still in her wayward mode of 'control'. She wants to control the outcome. A truly remorseful WS would be letting go of the outcome, and letting the BS be the one in control.
If it ends up derailing any hopes of R, I do want my W to be willing to work with me on the details of any potential D. If I go straight to the OBS without my wife's participation, it could likely fire up a lot of strife between my W and I. I guess my goal is now to periodically bring it up until I have her on board with telling her. If she never gets there (which I don't have much confidence in), I'll have to eventually suck it up and just do it.
Sorry, but your WS does not have a say in whether you inform the OBS or not. Again, if the WS were remorseful, they would support the BS no matter what the decision was (unless it involved some bodily harm/violence). The WS need not 'get on board' with that decision, same as the outcome of the M, be it R or D. The focus should be on what YOU need, not what the WS needs/wants, as they had already forfeit their involvement by bringing a 3rd party into the M.
If you take a look at some other tales of woe in this forum, you easily see which WS are truly remorseful, as they cede control over to their BS. They also prove themselves with their consistent actions and not with words. They look inward to try and find the causes, and address those causes, so that they do not stray again.
At the moment, your WS has yet to prove herself fully with her actions. Her crying and begging is a form of manipulation to prevent you from going the D route (this is not to say that you have to go on the D route). She NEEDS to prove herself to you, and the onus is on her on how to prove it to you.
Take your time and get yourself stable again. Focus on yourself first, then you will be able to make a clear headed decision.