YEA THATS WHAT I THOUGHT!!! because i recall you telling us how frustrated you were when his sisters threw all of these responsibilites on him and have him being 100 percent responsible for his parents' care w/o contributing in to help him out.... so i am not surprised that as a result-- this took ITS TOLL and affected your marriage
... i wish he would have just stand back, take a deep breath, relax and try to work it out with you instead of giving it all up cuz of BEING ALL EMOTIONALLY DRAINED OUT from BEING HIS FULL-TIME (100%) PARENTS' CARETAKER w/o his sisters' help... (sigh) NO OFFENSE... but his sisters are very selfish for doing this to him

like one ADer said... who knows he might realize that he made a terrible mistake, miss you guys and want to come back home to you guys.. THAT IS ONLY if you want him to "BACK"... 
HANG IN THERE! 