I've tried to catch up on your sitch, but it is awful long, so I likely missed some things & anything I say should be read w/ that in mind.
You did fine w/ the exchange over the friend. One question: do you and your H have any agreement or understanding regarding other people at this point? If you haven't you might want to have that discussion. Ultimately, if the situation continues toward D, ground rules will need to be established that you both abide by for the sake of your S. Don't know if you are there yet, but addressing Pam is one thing, but having a clear understanding is another.
One of the hardest things I wrestle w/ is that my W prefers to spend time w/ other people.
The other thing that stands out in your threads is a lack of other people to turn to IRL. You seem to entirely have come to depend on your H for your emotional needs, and he is not there right now. Even if he comes back, this is not healthy, and he is less likely to find coming back to a situation where you are so focused on getting your emotional needs met via the R. If I'm right here, it is something to address regardless.
You have a lot going on, and it really [censored] that your H has checked out when there is so much going on. That may be part of his issues, or at least the move to further distance.
Good luck to you.
Me: 50 W:43 S6, S3 M: 12 yrs. T: 17 M is bad & Not happy Bomb Mar '14 S 5 Feb '15 D Bomb 13 Apr '15 (but "no hurry") DB Coach May '15 Wants proceed on D Aug '15 Starting 1-on-1 negotiations Sept '15