About the inlaws. I think it is possible to be supportive of both the mlcer and the spouses. I know blood is thicker than water but we should not just be discarded after all these years.
ITA but also think it would be difficult for any parent, brother, sister etc. who is told (or hears it implied) "If you keep up a R w/ LBS, you will lose me" to respond "Go, then." I believe this emotional extortion is very often what happens. Yes the ILs should try to fight it but it seems many families (particularly those repeating an already entrenched history of D) don't have the moral fiber or emotional tools to do it. Not that this is an excuse, but w/ me it helps let go of bad feelings if I first seek to understand.