You already know labug is a goddess when it comes to advice, so listen to her.
Then stop the negative talk! Let him spew whatever he needs to spew and you keep on keepin' on. Do your GALs and 180s. Validate his feelings without agreeing with him.
It ain't over until it's over.
ME: 38 BF: 40 T: 10y, no kids, no M (by choice) BD: 7/14/14, BF admits to PA, wants out, lies about new R. 10/1/14: I move out, BF lies about move in with OW 12/4/14: OW confronted, reveals all the lies