He says this isn't what he really wants, but feels like the only way I will gain/not lose respect for him is if he goes.

Wow... now there's "pea soup" level fog.
Obviously, this is NOT about YOUR feelings.

Maybe what he really feels, is that he cant respect *himself*, unless he divorces you.

either that, or he's having an affair with that woman, of course.

Hang in there. dont give up on your husband!
(and dont say "whatever you want" to his divorce whims either....)