Has he had a full physical lately...being military he might be hesitant to mention that he has ED issues..
I know my H started having ED problems about the same age as your H...and that was also about the same time he decided to have an emotional affair...I guess he thought it might help things...when that didn't work it was a physical affair...
Basically he had a total mental breakdown with a MLC...your H sounds like he could be depressed...and I too question why he was single to such an older age???...the sudden drop off though is a bit odd...even for a man who is having an affair...something is bothering him...but until he is ready to deal with whatever it is...there isn't much you can do...
I am sorry I can't give you more then that...I do hope you get answers...but really he is the only one who has them...perhaps counseling for you or for the both of you IF he will go...
