I think you are still looking for the why, trying to figure out what happened and why it happened. But there is just no good answer, and you are putting yourself in pain over something that honestly had nothing to do with you. Sounds like you are still trying to put the puzzle together in your head, but there will always be pieces missing, and at some point you need to put it together enough to where you can look at it and accept it and move on.
I definitely recommend you stop looking at the crap and find something better to do with your time. Sounds a little like you are still holding out hope, and you need to let it go.
On a side note, their Facebook sounds awful. They are drooling all over each other? Talk about too much PDA. Gross. I can't stand people who do that on Facebook. That tells me they are extremely insecure and feel the need to prove something to everyone.. But whatever is on there shouldn't matter to you anymore. Forget those clowns and work on finding more positive things to fill your time..