Hi Lady Sailor
This must come as such a shock for you, i am so sorry!
Some medications for PD can trigger high levels of sexual behaviour but to leave your marriage is a little extreme and i am sure can't be blamed on the meds. Having said that, i do think that when someone has been told that they have a life changing condition it can take you down the road of selfish fulfilment .( I have PD so i am going to do what i want because i deserve it, I have enough to contend with) kind of thing. The diagnosis could have given your husband a bravery boost.
Relationships are so complex so no one on here can understand completely, If it were me then i would concentrate on myself and find someone to talk to in person about coping with what has just happened and where to go from here. Stay strong and good luck