Did RH perhaps become unbearable at home since 2010, when he stopped his "escapades", because they no longer brought him satisfaction? Did he also stop meeting with SWs? I can't imagine it.
Although I don't think, RH ever stopped murdering until he got caught, his fine ritual: AE/CS out of town ---> RH meeting and murdering a victim ---> AE/CS back from vacation and RH again the caring husband, this fine ritual may have been interrupted, and there had to be found a completely new system (murders despite presence of wife, in a car and/or in another state, disposing no longer at the LI beaches but far away). That may have affected his mood as a husband/father. For me it would explain, why they began to think about divorce. But of course I don't know, whether they couldn't get along since 2010.
Why AE fell in love again, when her husband turned out to be a SK, is a mystery to me.
MOO