I think you're having your annual rant.
Here is a thread you started last year:
Why I Hate the Lifestyle
It is similar to this one in that you are feeling bad about being rejected/unwanted and not getting a reason as to why. Yes, rejection sucks royally, but it's part of swinging.
I think you are taking this experience too personally.
I think expecting an explanation of why they no longer want to play with you or even be social friends (which hadn't yet developed) is expecting too much. I also think you'd be just as unhappy if they told you why they have dropped you.
This couple may have decided to take a break from swinging
because of how things were going with you. But you can't see it. Then, they decided to jump back in because this other couple got them feeling hopeful and interested once again in swinging. What I'm saying is that you're doing a lot of guessing and only upsetting yourself. You're accusing them of being untruthful and there is no need to, from what I can see, because you have no proof that they lied to you. You don't know what the story is and knowing it wouldn't make you feel better because the bottom line is YOU GOT DISSED.
I don't have experience with FaceBook, but I don't see that as the main issue here. I think your difficulty with being dumped - without explanation - is the issue.
I'm sorry this happened to you and I hope you're feeling better soon.
LM