I've just joined the board as well, sorry to see you here, too. I have already found some great info and ideas in the links, and having a course of action is always a good feeling.
While I was reading through your thread, I was thinking along the lines of what Sandi2 wrote above.
Did W or the two of you get any counseling in connection with her gastric bypass? It is a huge life change and counseling should be an integral part of the transition.
Also, losing both of your mothers is a very traumatic and life-changing event. It is not unusual for couples to divorce after the loss of a close family member.
It sounds to me, too, like she is addicted to the excitement of what she's into. It's sad, because it's a destructive path that doesn't do anything for one's character. One thing I think has worked for me when it comes to H's affair, is that I got him to tell me about it by being very quiet and asking open questions without judgment. I then talked about it very calmly and unemotionally now and then, with the quiet purpose of making it less secret (=exciting). He didn't like it much, but I think pulling things out into broad daylight takes a lot of the mystery and attraction away.
M 16 yrs, WH62, P54 3 adult blended kids EA 11/13, BD1 6/14 PA fall 14, BD2 2/15 Piecing 2015, BD3 12/15 Separated 4/16 WH moved OW in 5/16 Divorced 6/15/17